WiMax was designed to deliver last mile wireless broadband access as an alternative to cable and DSL. Its scalability offers flexible solutions for a range of possible deployment scenarios and it promises advantages such as: lower cost, wider coverage and higher capacity. However, fixed and mobile wireless access faces a stiff competition in the market of broadband services and the drive to build a profitable cost-effective network puts enormous pressure on the network design procedure. Automated cell planning techniques have been well studied and widely used across a range of wireless telephony applications. This work introduces a new approach employing a staged optimization framework to break an entire problem into several tasks which can balance thevarious objectives more effectively across the optimization process. The success of the approach is demonstrated using practical problem based on planning of WiMax service for the city of Newcastle in the UK, showing the improvement compared to a single stage optimization technique.
{"title":"A Staged Optimization Framework for Cost Optimized WiMax Network Design","authors":"V. Teterin, S. Hurley, S. M. Allen","doi":"10.1109/ICWMC.2008.46","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.46","url":null,"abstract":"WiMax was designed to deliver last mile wireless broadband access as an alternative to cable and DSL. Its scalability offers flexible solutions for a range of possible deployment scenarios and it promises advantages such as: lower cost, wider coverage and higher capacity. However, fixed and mobile wireless access faces a stiff competition in the market of broadband services and the drive to build a profitable cost-effective network puts enormous pressure on the network design procedure. Automated cell planning techniques have been well studied and widely used across a range of wireless telephony applications. This work introduces a new approach employing a staged optimization framework to break an entire problem into several tasks which can balance thevarious objectives more effectively across the optimization process. The success of the approach is demonstrated using practical problem based on planning of WiMax service for the city of Newcastle in the UK, showing the improvement compared to a single stage optimization technique.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133588887","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}
By using a single relay with best channel quality for cooperative diversity, opportunistic relaying achieves the same diversity gain as that achieved by more complex space-time coding. However, the failure probability of the best relay selection may become unacceptable when the number of relays increases. We propose a modified practical best relay selection scheme in this paper. The source is required to send an acknowledgement to the best relay, while contending relays will backoff when collision occurs. Simulation results show that the failure probability of relay selection is reduced by 2~3 orders with an extra overhead less than 2%.
{"title":"A Practical Cooperative Diversity Scheme Based on Opportunistic Relaying with Acknowledgement and Random Backoff","authors":"Danpu Liu, Jianjun Hao, Guangxin Yue","doi":"10.1109/ICWMC.2008.45","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.45","url":null,"abstract":"By using a single relay with best channel quality for cooperative diversity, opportunistic relaying achieves the same diversity gain as that achieved by more complex space-time coding. However, the failure probability of the best relay selection may become unacceptable when the number of relays increases. We propose a modified practical best relay selection scheme in this paper. The source is required to send an acknowledgement to the best relay, while contending relays will backoff when collision occurs. Simulation results show that the failure probability of relay selection is reduced by 2~3 orders with an extra overhead less than 2%.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"444 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115939028","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}
This paper constructed signal models of four types of signal in wireless communication, i.e. single user MIMO signal, single user single antenna signal, virtual MIMO signal and multibeam smart antenna signal first, and then proposed a method for blind identification of single user MIMO signal in step by step in noncooperation communication, when the unknown source was one of the four types by using MUSIC algorithm and forward-backward spatial smoothing algorithm to blindly estimate DOAs of the received signal in the first two steps, and use blind channel estimation in the third step. Simulation results show the feasibility of this method. There has not been any published literature reporting research results about this topic yet, so the results of this paper is of important value in both theory and application.
{"title":"A Method for Blind Identification of Single User MIMO Signal in Step by Step","authors":"Qinghua Chen, Xianzhong Xie","doi":"10.1109/ICWMC.2008.47","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.47","url":null,"abstract":"This paper constructed signal models of four types of signal in wireless communication, i.e. single user MIMO signal, single user single antenna signal, virtual MIMO signal and multibeam smart antenna signal first, and then proposed a method for blind identification of single user MIMO signal in step by step in noncooperation communication, when the unknown source was one of the four types by using MUSIC algorithm and forward-backward spatial smoothing algorithm to blindly estimate DOAs of the received signal in the first two steps, and use blind channel estimation in the third step. Simulation results show the feasibility of this method. There has not been any published literature reporting research results about this topic yet, so the results of this paper is of important value in both theory and application.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125985501","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}
A. Nickelsen, Morten N. Jensen, E. V. Matthiesen, H. Schwefel
Communication in wireless networks is affected by uncontrollable disturbances in the channel. Effects of these disturbances are exacerbated in networks with dynamic topologies and multiple hops. Lack of control of the channel complicates testing of such networks as test conditions are hard, or impossible, to reproduce. This paper describes how to create reproducible test conditions for these networks by emulating the wireless links. Emulation is performed by a topology emulator to which end-nodes are connected using wired links. In real-time, the emulator imposes packet drops and delays onto traffic between end-nodes. The imposed properties are based on simulations of node mobility, loss and delay models. Evaluation confirms that the testbed is capable of emulating links in real time and transparent to upper layer protocols. Additionally, the impact on test results is evaluated, such as increased network delays and reduction of bandwidth when loading the emulator. Finally, an outlook on advancing capabilities and how to integrate such in the emulator is presented.
{"title":"Scalable Emulation of Dynamic Multi-hop Topologies","authors":"A. Nickelsen, Morten N. Jensen, E. V. Matthiesen, H. Schwefel","doi":"10.1109/ICWMC.2008.44","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.44","url":null,"abstract":"Communication in wireless networks is affected by uncontrollable disturbances in the channel. Effects of these disturbances are exacerbated in networks with dynamic topologies and multiple hops. Lack of control of the channel complicates testing of such networks as test conditions are hard, or impossible, to reproduce. This paper describes how to create reproducible test conditions for these networks by emulating the wireless links. Emulation is performed by a topology emulator to which end-nodes are connected using wired links. In real-time, the emulator imposes packet drops and delays onto traffic between end-nodes. The imposed properties are based on simulations of node mobility, loss and delay models. Evaluation confirms that the testbed is capable of emulating links in real time and transparent to upper layer protocols. Additionally, the impact on test results is evaluated, such as increased network delays and reduction of bandwidth when loading the emulator. Finally, an outlook on advancing capabilities and how to integrate such in the emulator is presented.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129844446","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}
A. Salehan, M. Robatmili, M. Abrishami, A. Movaghar
One of the most important challenges in mobile Ad-hoc networks is simulation. The simulation of these networks based on the accessible simulation techniques, which are based on packet, is a demanding and time-consuming task. Moreover, with the complexity of the network and the increase in the numbers of the nodes, it is likely to take a long time. This is because these simulators, one by one, regard the acts of all moving packets in one part of the network, and process these acts as a series of events. Since the number of the events is high in this method, the simulation takes time. Nowadays, in wired networks, several methods have been suggested to lessen the time of simulation; one example can be the technique of model summarizing which is well used in these networks. The proposed method in this paper represents a simulation technique based on Fluid flow for Ad-hoc networks. Then we can implement the routing protocols according to the proposed method. Finally, the routing protocols in such networks are evaluated based on the amount they accelerate the simulation.
{"title":"A Comparison of Various Routing Protocols in Mobile Ad-Hoc Networks (MANETs) with the Use of Fluid Flow Simulation Method","authors":"A. Salehan, M. Robatmili, M. Abrishami, A. Movaghar","doi":"10.1109/ICWMC.2008.41","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.41","url":null,"abstract":"One of the most important challenges in mobile Ad-hoc networks is simulation. The simulation of these networks based on the accessible simulation techniques, which are based on packet, is a demanding and time-consuming task. Moreover, with the complexity of the network and the increase in the numbers of the nodes, it is likely to take a long time. This is because these simulators, one by one, regard the acts of all moving packets in one part of the network, and process these acts as a series of events. Since the number of the events is high in this method, the simulation takes time. Nowadays, in wired networks, several methods have been suggested to lessen the time of simulation; one example can be the technique of model summarizing which is well used in these networks. The proposed method in this paper represents a simulation technique based on Fluid flow for Ad-hoc networks. Then we can implement the routing protocols according to the proposed method. Finally, the routing protocols in such networks are evaluated based on the amount they accelerate the simulation.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130269368","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}
Many of applications in vehicular ad hoc networks (VANET) are based on dissemination of information, so broadcasting is a fundamental service in these networks. Broadcasting is a difficult task since vehicular networks often lack continuous end-to-end connectivity and have large variations in node densities. In this paper we present a method that improves the reception rates of broadcast messages by overcoming problem of connectivity gaps. In our method, every forwarder of message when facing a gap sends small messages periodically. These methods are used to understand entrance of a new vehicle that can be selected as the next forwarder of message. We have evaluated the performance of proposed protocol in NS2 under various network conditions.
{"title":"A Reliable Method for Disseminating Safety Information in Vehicular Ad Hoc Networks Considering Fragmentation Problem","authors":"S. Khakbaz, M. Fathy","doi":"10.1109/ICWMC.2008.74","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.74","url":null,"abstract":"Many of applications in vehicular ad hoc networks (VANET) are based on dissemination of information, so broadcasting is a fundamental service in these networks. Broadcasting is a difficult task since vehicular networks often lack continuous end-to-end connectivity and have large variations in node densities. In this paper we present a method that improves the reception rates of broadcast messages by overcoming problem of connectivity gaps. In our method, every forwarder of message when facing a gap sends small messages periodically. These methods are used to understand entrance of a new vehicle that can be selected as the next forwarder of message. We have evaluated the performance of proposed protocol in NS2 under various network conditions.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126273095","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}
The rapid development in the mobile computing domain has significantly expedited the utilization of context-aware systems. Present approaches utilizing awareness of context specialize on their unique domain of employment. Although similarities between those approaches exist, the correspondent concepts and systems are vastly heterogeneous. Another aspect of the rapid evolution of mobile computing is the emergence of a highly heterogeneous spectrum of technologies. This issue complicates the demand for interoperability, which is inherent in mobile computing environments. However, as with context-aware research, most of present approaches addressing heterogeneity are specializing on solving the problem domain-specifically. In this paper, we present a conceptualization on generalizing both context-awareness and heterogeneity-handling in mobile computing environments. Concluding, we derive a general architecture, which overcomes the heterogeneity issues present in both context-awareness and interoperability domains.
{"title":"A Generalized Context-aware Architecture in Heterogeneous Mobile Computing Environments","authors":"R. Schmohl, U. Baumgarten","doi":"10.1109/ICWMC.2008.59","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.59","url":null,"abstract":"The rapid development in the mobile computing domain has significantly expedited the utilization of context-aware systems. Present approaches utilizing awareness of context specialize on their unique domain of employment. Although similarities between those approaches exist, the correspondent concepts and systems are vastly heterogeneous. Another aspect of the rapid evolution of mobile computing is the emergence of a highly heterogeneous spectrum of technologies. This issue complicates the demand for interoperability, which is inherent in mobile computing environments. However, as with context-aware research, most of present approaches addressing heterogeneity are specializing on solving the problem domain-specifically. In this paper, we present a conceptualization on generalizing both context-awareness and heterogeneity-handling in mobile computing environments. Concluding, we derive a general architecture, which overcomes the heterogeneity issues present in both context-awareness and interoperability domains.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128031415","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}
End-to-end delay and loss probability are two important parameters for evaluating the performance of multihop ad hoc networks. One of the main reasons for increasing the value of those parameters; is the buffer management scheme in the intermediate nodes. The number of hops that the packet traversed is not taken into account in most existing buffer management schemes. Dropping a packet which traversed a large number of hops; results in more retransmission overhead and therefore more congestion in networks than dropping a packet with a small number of hops. In this paper, we propose a buffer management scheme named hop-aware buffering (HAB). HAB is based on virtual partitioning of the buffer at each node according to the number of hops that the packets traversed from source to relaying node. The partitions are correlated and dynamically changed according to the traffic load. An analytical model based on a 4-dimensional Markov chain and simulation is carried out. The results show that HAB outperforms droptail in terms of end-to-end delay and loss probability.
{"title":"Performance Evaluation of Hop-Aware Buffer Management Scheme in Multihop Ad Hoc Networks","authors":"M. Kalil, H. Al-Mahdi, A. Mitschele-Thiel","doi":"10.1109/ICWMC.2008.54","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.54","url":null,"abstract":"End-to-end delay and loss probability are two important parameters for evaluating the performance of multihop ad hoc networks. One of the main reasons for increasing the value of those parameters; is the buffer management scheme in the intermediate nodes. The number of hops that the packet traversed is not taken into account in most existing buffer management schemes. Dropping a packet which traversed a large number of hops; results in more retransmission overhead and therefore more congestion in networks than dropping a packet with a small number of hops. In this paper, we propose a buffer management scheme named hop-aware buffering (HAB). HAB is based on virtual partitioning of the buffer at each node according to the number of hops that the packets traversed from source to relaying node. The partitions are correlated and dynamically changed according to the traffic load. An analytical model based on a 4-dimensional Markov chain and simulation is carried out. The results show that HAB outperforms droptail in terms of end-to-end delay and loss probability.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131890563","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}
S. Panagiotou, C. Tsitouri, T. D. Dimousios, C. Capsalis
A low cost and profile switched beam array suitable for 2.4 GHz ISM and WLAN applications is proposed in this paper. The array comprises eight wire elements lying on the horizontal plane and a set of four possible, switching, beam patterns is provided. Sufficient front gain and input impedance matching is achieved with the aid of a simple genetic algorithm.
{"title":"A New, Compact, Low Cost Switched Beam Array for ISM and WLAN Applications at 2.4 GHz","authors":"S. Panagiotou, C. Tsitouri, T. D. Dimousios, C. Capsalis","doi":"10.1109/ICWMC.2008.26","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.26","url":null,"abstract":"A low cost and profile switched beam array suitable for 2.4 GHz ISM and WLAN applications is proposed in this paper. The array comprises eight wire elements lying on the horizontal plane and a set of four possible, switching, beam patterns is provided. Sufficient front gain and input impedance matching is achieved with the aid of a simple genetic algorithm.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133824542","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}
Mobile ad hoc networks (MANETs) are spontaneously formed with a set of wireless nodes without any existing infrastructure or administrative support. The intrinsic characteristics of these networks such as the dynamic topology and the scarcity of resources mainly bandwidth and nodes battery life make network management process a challenging task. In this paper, we present the design and a performance evaluation of a distributed policy management system that aims to enable self-QoS-management of MANETs. The key idea is to extend policy decision point (PDP) functionalities to every mobile ad hoc node in order to support self-configuration and self-adaptation capabilities. We propose the management of the MANET in a fully distributed manner using a new named DPMP for Distributed Policy Management Protocol. First, we present our decentralized framework. Then, we evaluate the proposed policy distribution mechanism through simulations. Results show that the protocol incurs low latency and message overhead for policies distribution while varying node mobility, network size and density.
{"title":"Towards Autonomous Mobile Ad Hoc Networks: A Distributed Policy-Based Management Approach","authors":"M. Ayari, F. Kamoun, G. Pujolle","doi":"10.1109/ICWMC.2008.17","DOIUrl":"https://doi.org/10.1109/ICWMC.2008.17","url":null,"abstract":"Mobile ad hoc networks (MANETs) are spontaneously formed with a set of wireless nodes without any existing infrastructure or administrative support. The intrinsic characteristics of these networks such as the dynamic topology and the scarcity of resources mainly bandwidth and nodes battery life make network management process a challenging task. In this paper, we present the design and a performance evaluation of a distributed policy management system that aims to enable self-QoS-management of MANETs. The key idea is to extend policy decision point (PDP) functionalities to every mobile ad hoc node in order to support self-configuration and self-adaptation capabilities. We propose the management of the MANET in a fully distributed manner using a new named DPMP for Distributed Policy Management Protocol. First, we present our decentralized framework. Then, we evaluate the proposed policy distribution mechanism through simulations. Results show that the protocol incurs low latency and message overhead for policies distribution while varying node mobility, network size and density.","PeriodicalId":308667,"journal":{"name":"2008 The Fourth International Conference on Wireless and Mobile Communications","volume":"1119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116069847","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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