Pub Date : 2007-12-04DOI: 10.1109/ISWCS.2007.4392291
S. Ali, A. Fakoorian, H. Taheri
This paper presents an optimization framework for a wireless sensor network in which the sensor network uses multipath diversity in the network layer and erasure codes. We use a distributed sink where information arrives at the sink via multiple proxy nodes, called "prongs" in [1]. The sender node uses Reed-Solomon erasure coding and splits each packet into multiple fragments and transmits the fragments over multiple disjoint paths. The erasure coding allows the sink to reconstruct the packet if it receives a number of fragments equal to or higher than the number of fragments in the original packet. The total size of fragments and the number of fragments that should be transmitted on each path are design parameters that can be tuned to adapt to the traffic of the network nodes, number of parallel paths and availability probability of each link. The total cost due to packet loss and fragment transmission using such systems is analyzed in the presence of disjoint parallel paths. Based on the total cost, we investigate the trade-off between the system reliability and the cost of fragment transmissions. The problem of optimizing the number of parity fragments under different network situations is treated numerically.
{"title":"Optimum Reed-Solomon Erasure Coding in Fault Tolerant Sensor Networks","authors":"S. Ali, A. Fakoorian, H. Taheri","doi":"10.1109/ISWCS.2007.4392291","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392291","url":null,"abstract":"This paper presents an optimization framework for a wireless sensor network in which the sensor network uses multipath diversity in the network layer and erasure codes. We use a distributed sink where information arrives at the sink via multiple proxy nodes, called \"prongs\" in [1]. The sender node uses Reed-Solomon erasure coding and splits each packet into multiple fragments and transmits the fragments over multiple disjoint paths. The erasure coding allows the sink to reconstruct the packet if it receives a number of fragments equal to or higher than the number of fragments in the original packet. The total size of fragments and the number of fragments that should be transmitted on each path are design parameters that can be tuned to adapt to the traffic of the network nodes, number of parallel paths and availability probability of each link. The total cost due to packet loss and fragment transmission using such systems is analyzed in the presence of disjoint parallel paths. Based on the total cost, we investigate the trade-off between the system reliability and the cost of fragment transmissions. The problem of optimizing the number of parity fragments under different network situations is treated numerically.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129909349","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392456
Jie Xu, G. Tu, Yuming Jiang
In multi-hop wireless networks, active nodes compete for the sharing channel with nodes in the same range. In this paper, we show that a large fraction of the competition can be seen as unnecessary. In addition, we present that with the aid of routing information, the unnecessary competition can be alleviated and consequently the network performance improved.
{"title":"Unnecessary Competition in Multi-hop Wireless Networks","authors":"Jie Xu, G. Tu, Yuming Jiang","doi":"10.1109/ISWCS.2007.4392456","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392456","url":null,"abstract":"In multi-hop wireless networks, active nodes compete for the sharing channel with nodes in the same range. In this paper, we show that a large fraction of the competition can be seen as unnecessary. In addition, we present that with the aid of routing information, the unnecessary competition can be alleviated and consequently the network performance improved.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122233088","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392451
M. Siddiqua, S. Sheikh
This paper discusses various strategies that are currently being employed to prevent the frequency spectra from getting saturated due to the dramatically increasing growth of users & applications requiring radio spectrum. It discusses the optimal spectrum management mainly for satellite systems. It also goes on to discuss the future actions that can be taken to effectively utilize the spectrum.
{"title":"Strategies for Effective Frequency Allocations for Satellite Communications","authors":"M. Siddiqua, S. Sheikh","doi":"10.1109/ISWCS.2007.4392451","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392451","url":null,"abstract":"This paper discusses various strategies that are currently being employed to prevent the frequency spectra from getting saturated due to the dramatically increasing growth of users & applications requiring radio spectrum. It discusses the optimal spectrum management mainly for satellite systems. It also goes on to discuss the future actions that can be taken to effectively utilize the spectrum.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125494157","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392325
N. Riato, Federico Serrelli, Andrea Sala, A. Capone
WiMAX IEEE802.16e systems are intended to provide high spectral efficiency in order to support services with challenging QoS constraints in heterogeneous scenarios. However, when addressing such goal, it is important to consider in detail the impact of deployment related issues. Inter-cell interference is one of them and plays a relevant role in limiting system level performances. On the other side, WiMAX standard provides several useful features at both PHY and MAC layer for facing propagation channel impairments and that can be exploited in order to combat inter-cell interference. In this paper an analysis of the main features influencing the inter-cell interference scenario is provided and interference mitigation strategies are proposed and evaluated through system level simulations.
{"title":"Interference Mitigation Strategies for WiMAX Networks","authors":"N. Riato, Federico Serrelli, Andrea Sala, A. Capone","doi":"10.1109/ISWCS.2007.4392325","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392325","url":null,"abstract":"WiMAX IEEE802.16e systems are intended to provide high spectral efficiency in order to support services with challenging QoS constraints in heterogeneous scenarios. However, when addressing such goal, it is important to consider in detail the impact of deployment related issues. Inter-cell interference is one of them and plays a relevant role in limiting system level performances. On the other side, WiMAX standard provides several useful features at both PHY and MAC layer for facing propagation channel impairments and that can be exploited in order to combat inter-cell interference. In this paper an analysis of the main features influencing the inter-cell interference scenario is provided and interference mitigation strategies are proposed and evaluated through system level simulations.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128730153","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392396
Z. Madini, A. Bennadji, E. Ngoya
Accurate modelling of memory effects of RF amplifiers has becomes a prime importance in the design process for the new generations of communications systems. A tremendous amount of modeling techniques has been proposed lately. A capital point in these behavioral modeling is the ease and accuracy of model parameter extraction process along with the model run time efficiency in system level simulation tools. This paper proposes an new and effective extraction technique for dynamic Volterra series based model, as well as a model implementation technique in system level simulation.
{"title":"A Novel Extraction Technique of Long Term Memory Effects in Solid State Amplifiers Based on Compound Dynamic Volterra Models Structure","authors":"Z. Madini, A. Bennadji, E. Ngoya","doi":"10.1109/ISWCS.2007.4392396","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392396","url":null,"abstract":"Accurate modelling of memory effects of RF amplifiers has becomes a prime importance in the design process for the new generations of communications systems. A tremendous amount of modeling techniques has been proposed lately. A capital point in these behavioral modeling is the ease and accuracy of model parameter extraction process along with the model run time efficiency in system level simulation tools. This paper proposes an new and effective extraction technique for dynamic Volterra series based model, as well as a model implementation technique in system level simulation.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134459304","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392443
Yuanyuan Ma, M. Pätzold
This paper investigates the performance of multiple- input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems using different wideband MIMO channel models. The considered MIMO channel models are based on the geometrical elliptical model and the geometrical one-ring model. The spatial correlation effects due to the limited antenna spacings and the Doppler effect caused by the movement of the receiver are studied separately. It is shown that increasing the antenna spacings leads to a higher diversity gain. The relevant range of the antenna spacings that has a strong influence on the system performance is obtained through simulations. When the antenna spacings exceed the determined range, then the diversity gain does not increase significantly. Moreover, to achieve the same system performance, the MIMO-OFDM system employing the one-ring model requires larger antenna spacings than using the elliptical channel model. Furthermore, the influence of the maximum Doppler frequency has been studied under perfect and imperfect channel state information (CSI). It is demonstrated that system performance degradations occur if the maximum Doppler frequency increases, especially in case of imperfect CSI.
{"title":"Performance Comparison of Space-Time Coded MIMO-OFDM Systems Using Different Wideband MIMO Channel Models","authors":"Yuanyuan Ma, M. Pätzold","doi":"10.1109/ISWCS.2007.4392443","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392443","url":null,"abstract":"This paper investigates the performance of multiple- input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems using different wideband MIMO channel models. The considered MIMO channel models are based on the geometrical elliptical model and the geometrical one-ring model. The spatial correlation effects due to the limited antenna spacings and the Doppler effect caused by the movement of the receiver are studied separately. It is shown that increasing the antenna spacings leads to a higher diversity gain. The relevant range of the antenna spacings that has a strong influence on the system performance is obtained through simulations. When the antenna spacings exceed the determined range, then the diversity gain does not increase significantly. Moreover, to achieve the same system performance, the MIMO-OFDM system employing the one-ring model requires larger antenna spacings than using the elliptical channel model. Furthermore, the influence of the maximum Doppler frequency has been studied under perfect and imperfect channel state information (CSI). It is demonstrated that system performance degradations occur if the maximum Doppler frequency increases, especially in case of imperfect CSI.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129143613","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392440
K. Küçük, A. Kavak, H. Yiğit
We introduce a smart antenna (SA) module to be used in OMNeT++ for wireless sensor networks (WSN). This module is a collection of tools in OMNeT++ for adding smart antenna capability to a central node in WSNs. It is based on sectoral sweeper (SS) scheme which was shown to provide efficient task management and easy localization scheme. The number of sensing nodes, energy consumption of nodes, and data traffic carried in the network are reduced with the SS. OMNeT++ is an open source object-oriented modular discrete event network simulator consisting of hierarchically nested modules. With the SA module, desired task region can be specified by a task beam with changing beam width and beam direction parameters in the OMNeT++ configuration file. In addition, each node in the network model that uses SA module has capability of Mobility framework which is intended to support wireless and mobile simulations within OMNeT++. The simulation results provide performance evaluation using the developed module in OMNeT++ for WSNs.
{"title":"A Smart Antenna Module Using OMNeT++ for Wireless Sensor Network Simulation","authors":"K. Küçük, A. Kavak, H. Yiğit","doi":"10.1109/ISWCS.2007.4392440","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392440","url":null,"abstract":"We introduce a smart antenna (SA) module to be used in OMNeT++ for wireless sensor networks (WSN). This module is a collection of tools in OMNeT++ for adding smart antenna capability to a central node in WSNs. It is based on sectoral sweeper (SS) scheme which was shown to provide efficient task management and easy localization scheme. The number of sensing nodes, energy consumption of nodes, and data traffic carried in the network are reduced with the SS. OMNeT++ is an open source object-oriented modular discrete event network simulator consisting of hierarchically nested modules. With the SA module, desired task region can be specified by a task beam with changing beam width and beam direction parameters in the OMNeT++ configuration file. In addition, each node in the network model that uses SA module has capability of Mobility framework which is intended to support wireless and mobile simulations within OMNeT++. The simulation results provide performance evaluation using the developed module in OMNeT++ for WSNs.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127166002","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392445
P. Rossi, Parisa Pakniat, R. Müller, O. Edfors
An iterative receiver for multiple-input multiple- output (MIMO) orthogonal frequency division multiplexing (OFDM) wireless systems is presented and tested on channel measurements from a real indoor scenario. The receiver jointly performs channel estimation and multiuser detection, with soft information iteratively provided by the singleuser decoders. Results for the performance are presented in terms of bit error rate (BER) and relative minimum mean square error (MMSE) vs signal-to-noise ratio (SNR). Comparison with the single-user bound (SUB) shows a loss in performance due to frequency correlation.
{"title":"Iterative Joint Channel Estimation and Multiuser Detection for Wireless MIMO-OFDM Systems: Performance in a Real Indoor Scenario","authors":"P. Rossi, Parisa Pakniat, R. Müller, O. Edfors","doi":"10.1109/ISWCS.2007.4392445","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392445","url":null,"abstract":"An iterative receiver for multiple-input multiple- output (MIMO) orthogonal frequency division multiplexing (OFDM) wireless systems is presented and tested on channel measurements from a real indoor scenario. The receiver jointly performs channel estimation and multiuser detection, with soft information iteratively provided by the singleuser decoders. Results for the performance are presented in terms of bit error rate (BER) and relative minimum mean square error (MMSE) vs signal-to-noise ratio (SNR). Comparison with the single-user bound (SUB) shows a loss in performance due to frequency correlation.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125277629","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392457
Azadeh Ettefagh, M. Kuhn, A. Wittneben
Conventional half-duplex relaying suffers from a pre- log factor of frac12 in the capacity equation which reduces the spectral efficiency significantly. On the other hand half-duplex two-way relaying, which can compensate this spectrum efficiency loss and could be a suitable substitute for conventional relaying, requires two nodes to transmit at the same time and frequency. Therefore to realise two-way relaying a modification of the current IEEE 802.11/e Medium Access Control (MAC) is necessary. In this paper we propose an appropriate MAC scheme for two-way relaying. The main objective is to investigate for realistic network configurations how much the throughput is improved by two-way and semi-two-way relaying under the proposed MAC compared to conventional relaying.
{"title":"Throughput Performance of Two-way Relaying in IEEE 802.11 Networks","authors":"Azadeh Ettefagh, M. Kuhn, A. Wittneben","doi":"10.1109/ISWCS.2007.4392457","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392457","url":null,"abstract":"Conventional half-duplex relaying suffers from a pre- log factor of frac12 in the capacity equation which reduces the spectral efficiency significantly. On the other hand half-duplex two-way relaying, which can compensate this spectrum efficiency loss and could be a suitable substitute for conventional relaying, requires two nodes to transmit at the same time and frequency. Therefore to realise two-way relaying a modification of the current IEEE 802.11/e Medium Access Control (MAC) is necessary. In this paper we propose an appropriate MAC scheme for two-way relaying. The main objective is to investigate for realistic network configurations how much the throughput is improved by two-way and semi-two-way relaying under the proposed MAC compared to conventional relaying.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127052948","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 : 2007-12-04DOI: 10.1109/ISWCS.2007.4392422
Lei Wang, R. D. Lamare
In this paper, we study the performance of blind adaptive beamforming algorithms for smart antennas in realistic environments. A constrained constant modulus (CCM) design criterion is described and used for deriving a recursive least squares (RLS) type optimization algorithm. Furthermore, two kinds of scenarios are considered in the paper for analyzing its performance. Simulations are performed to compare the performance of the proposed method to other well-known methods for blind adaptive beamforming. Results indicate that the proposed method has a significant faster convergence rate, better robustness to changeable environments and better tracking capability.
{"title":"Constrained Constant Modulus RLS-based Blind Adaptive Beamforming Algorithm for Smart Antennas","authors":"Lei Wang, R. D. Lamare","doi":"10.1109/ISWCS.2007.4392422","DOIUrl":"https://doi.org/10.1109/ISWCS.2007.4392422","url":null,"abstract":"In this paper, we study the performance of blind adaptive beamforming algorithms for smart antennas in realistic environments. A constrained constant modulus (CCM) design criterion is described and used for deriving a recursive least squares (RLS) type optimization algorithm. Furthermore, two kinds of scenarios are considered in the paper for analyzing its performance. Simulations are performed to compare the performance of the proposed method to other well-known methods for blind adaptive beamforming. Results indicate that the proposed method has a significant faster convergence rate, better robustness to changeable environments and better tracking capability.","PeriodicalId":261480,"journal":{"name":"2007 4th International Symposium on Wireless Communication Systems","volume":"283 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124520245","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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