In this paper, we present a novel centralized ARQ technique based on the lower bound on information combining. Contrary to conventional approaches where relays are selected according to the end-to-end quality of the link or decoding status of the relay, we select the minimum number of relays which suffice to allow the destination to successfully decode. Generally, it is believed that if a relay is unable to decode successfully it is useless, here we show that a relay with failures is also useful. We demonstrate that a system considering relays with successful decoding as well as with failures delivers much better performance than a system only considering successful relays for forwarding.
{"title":"Information combining based ARQ in relay networks","authors":"A. Khan, V. Kuhn, S. Vorkoper","doi":"10.1109/EW.2009.5357981","DOIUrl":"https://doi.org/10.1109/EW.2009.5357981","url":null,"abstract":"In this paper, we present a novel centralized ARQ technique based on the lower bound on information combining. Contrary to conventional approaches where relays are selected according to the end-to-end quality of the link or decoding status of the relay, we select the minimum number of relays which suffice to allow the destination to successfully decode. Generally, it is believed that if a relay is unable to decode successfully it is useless, here we show that a relay with failures is also useful. We demonstrate that a system considering relays with successful decoding as well as with failures delivers much better performance than a system only considering successful relays for forwarding.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134145082","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}
Soft frequency reuse is a strong tool for co-channel interference mitigation in cellular OFDMA/LTE networks. The performance of such networks significantly depends on the configuration of the power masks that implement the soft frequency reuse patterns. In this paper, we investigate the performance of different power mask configurations against the optimal case, in which a central entity optimally distributes power and resource blocks among the users of the network. It is shown that large differences exist between the performance of different mask types and the optimal case in both, the overall cell throughput, as well as the cell-edge user performance.1
{"title":"Optimal power masking in soft frequency reuse based OFDMA networks","authors":"M. Bohge, J. Gross, A. Wolisz","doi":"10.1109/EW.2009.5358004","DOIUrl":"https://doi.org/10.1109/EW.2009.5358004","url":null,"abstract":"Soft frequency reuse is a strong tool for co-channel interference mitigation in cellular OFDMA/LTE networks. The performance of such networks significantly depends on the configuration of the power masks that implement the soft frequency reuse patterns. In this paper, we investigate the performance of different power mask configurations against the optimal case, in which a central entity optimally distributes power and resource blocks among the users of the network. It is shown that large differences exist between the performance of different mask types and the optimal case in both, the overall cell throughput, as well as the cell-edge user performance.1","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133762544","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}
Lu Lu, Gang Wu, Haiyang Huang, Shaoqian Li, F. Sun
In this paper, we propose a novel codebook-based precoding design for orthogonal space-time block codes (OSTBCs) over multiple-input multiple-output (MIMO) channels with finite rate feedback. The proposed approach aims at providing better system performance by utilizing the property of OSTBCs and the prior information of the statistical antenna correlation. Under a new way of controlling the average transmit power, a novel structure of precoding matrix is given, which is different from the unitary precoding. Moreover, with the information of the transmit correlation matrix, the codebook design is generalized to correlated channels. Both theoretical analyses and simulation results are provided.
{"title":"Improved codebook design for precoding of OSTBCs in correlated MIMO channels with finite rate feedback","authors":"Lu Lu, Gang Wu, Haiyang Huang, Shaoqian Li, F. Sun","doi":"10.1109/EW.2009.5357994","DOIUrl":"https://doi.org/10.1109/EW.2009.5357994","url":null,"abstract":"In this paper, we propose a novel codebook-based precoding design for orthogonal space-time block codes (OSTBCs) over multiple-input multiple-output (MIMO) channels with finite rate feedback. The proposed approach aims at providing better system performance by utilizing the property of OSTBCs and the prior information of the statistical antenna correlation. Under a new way of controlling the average transmit power, a novel structure of precoding matrix is given, which is different from the unitary precoding. Moreover, with the information of the transmit correlation matrix, the codebook design is generalized to correlated channels. Both theoretical analyses and simulation results are provided.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117158334","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}
Residential indoor measurements of the line of sight (LOS) and non-LOS (NLOS) distance dependent path loss are analysed from 10 MHz to 4.5 GHz. For these measurements, a time domain sounder is used to interrogate the propagation channel in two ways: static, and dynamic. For the static measurements, the transmit and receive antennas are located at predefined locations and the sounding premises vacated before capturing channel impulse responses (CIRs). For the dynamic measurements, a person displaces the receive antenna over predefined paths while the sounder stores CIRs at specific time intervals. The measurements are compared and analysed, and a modelling scheme is proposed for the continuous simulation of the distance dependent path loss.
{"title":"Static and dynamic measurement of the UWB distance dependent path loss","authors":"R. Cepeda, J. Mcgeehan, M. Umaa, M. Beach","doi":"10.1109/EW.2009.5357756","DOIUrl":"https://doi.org/10.1109/EW.2009.5357756","url":null,"abstract":"Residential indoor measurements of the line of sight (LOS) and non-LOS (NLOS) distance dependent path loss are analysed from 10 MHz to 4.5 GHz. For these measurements, a time domain sounder is used to interrogate the propagation channel in two ways: static, and dynamic. For the static measurements, the transmit and receive antennas are located at predefined locations and the sounding premises vacated before capturing channel impulse responses (CIRs). For the dynamic measurements, a person displaces the receive antenna over predefined paths while the sounder stores CIRs at specific time intervals. The measurements are compared and analysed, and a modelling scheme is proposed for the continuous simulation of the distance dependent path loss.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124262073","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}
In this paper we study an amplify-and-forward broadband relay network with cyclic delay diversity. Our main focus resides in reducing the channel estimation error by exploiting the cyclic shift and the properties of the fast Fourier transformation (FFT). Besides the improvement cyclic delay diversity is already delivering at almost no cost at the relays, we show that the bit error rate can be reduced. Furthermore, we investigate channel estimation at the destination and compare the results from scenarios with perfect channel knowledge. It is shown that the performance of the proposed noise reduced channel estimation for a relay network with and without cyclic delay diversity strongly depends on the frequency selectivity of the channels.
{"title":"Reducing the channel estimation error for relay networks with cyclic delay diversity","authors":"S. Vorkoper, V. Kuhn","doi":"10.1109/EW.2009.5357975","DOIUrl":"https://doi.org/10.1109/EW.2009.5357975","url":null,"abstract":"In this paper we study an amplify-and-forward broadband relay network with cyclic delay diversity. Our main focus resides in reducing the channel estimation error by exploiting the cyclic shift and the properties of the fast Fourier transformation (FFT). Besides the improvement cyclic delay diversity is already delivering at almost no cost at the relays, we show that the bit error rate can be reduced. Furthermore, we investigate channel estimation at the destination and compare the results from scenarios with perfect channel knowledge. It is shown that the performance of the proposed noise reduced channel estimation for a relay network with and without cyclic delay diversity strongly depends on the frequency selectivity of the channels.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126649490","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}
Péter Vingelmann, Peter Zanaty, F. Fitzek, H. Charaf
This paper describes the implementation of network coding on OpenGL-enabled graphics cards. Network coding is an interesting approach to increase the capacity and robustness in multi-hop networks. The current problem is to implement random linear network coding on mobile devices which are limited in computational power, energy, and memory. Some mobile devices are equipped with a 3D graphics accelerator, which could be used to do most of the RLNC related calculations. Such a cross-over have already been used in computationally demanding research tasks as in physics or medicine. As a first step the paper focuses on the implementation of RLNC using the OpenGL library and NVidia's Cg toolkit on desktop PCs and laptops. Several measurement results show that the implementation on the graphics accelerator is outperforming the CPU by a significant margin. The OpenGL implementation performs relatively better with larger generation sizes due to the parallel nature of GPUs. Therefore the paper shows an appealing solution for the future to perform network coding on mobile devices.
{"title":"Implementation of random linear network coding on OpenGL-enabled graphics cards","authors":"Péter Vingelmann, Peter Zanaty, F. Fitzek, H. Charaf","doi":"10.1109/EW.2009.5357971","DOIUrl":"https://doi.org/10.1109/EW.2009.5357971","url":null,"abstract":"This paper describes the implementation of network coding on OpenGL-enabled graphics cards. Network coding is an interesting approach to increase the capacity and robustness in multi-hop networks. The current problem is to implement random linear network coding on mobile devices which are limited in computational power, energy, and memory. Some mobile devices are equipped with a 3D graphics accelerator, which could be used to do most of the RLNC related calculations. Such a cross-over have already been used in computationally demanding research tasks as in physics or medicine. As a first step the paper focuses on the implementation of RLNC using the OpenGL library and NVidia's Cg toolkit on desktop PCs and laptops. Several measurement results show that the implementation on the graphics accelerator is outperforming the CPU by a significant margin. The OpenGL implementation performs relatively better with larger generation sizes due to the parallel nature of GPUs. Therefore the paper shows an appealing solution for the future to perform network coding on mobile devices.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"163 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126659045","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}
Today's radio frequency regulation is undergoing fundamental changes. There is a high demand for radio frequency spectrum for data communication but no blank spots in the frequency assignments plan. Under the approach of coexistence and cognitive radio, spectrum is made available to systems if a license holder is not using it at a given geographic location or time. In this case multiple systems can compete for spectrum access. In this paper we present an approach how multiple IEEE 802.16 systems can coexist in the same frequency band. The key idea is to define rules how the systems can schedule their transmissions to achieve more regular and therefore more predictable channel occupation. The approach does not require carrier sensing before normal data transmission. Analytic and simulation results are presented showing how systems can estimate available capacity and the impact of their behaviour to own and overall performance. Therefore results for the collision probability are derived.
{"title":"IEEE 802.16 coexistence through regular channel occupation","authors":"M. Muhleisen, R. Jennen, M. Siddique, C. Gorg","doi":"10.1109/EW.2009.5357967","DOIUrl":"https://doi.org/10.1109/EW.2009.5357967","url":null,"abstract":"Today's radio frequency regulation is undergoing fundamental changes. There is a high demand for radio frequency spectrum for data communication but no blank spots in the frequency assignments plan. Under the approach of coexistence and cognitive radio, spectrum is made available to systems if a license holder is not using it at a given geographic location or time. In this case multiple systems can compete for spectrum access. In this paper we present an approach how multiple IEEE 802.16 systems can coexist in the same frequency band. The key idea is to define rules how the systems can schedule their transmissions to achieve more regular and therefore more predictable channel occupation. The approach does not require carrier sensing before normal data transmission. Analytic and simulation results are presented showing how systems can estimate available capacity and the impact of their behaviour to own and overall performance. Therefore results for the collision probability are derived.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127681693","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}
In this paper it is presented a study of the optimum number of radiating elements in a MIMO array for different portable devices working in the 5.6 GHz band. The array configurations are formed using a Vivaldi antenna as radiating element. This study tries to clarify how many elements are possible to allocate in the different form factors to achieve the best possible effective diversity gain (EDG). Laptop, PDA and PCMCIA are the form factors that are used in this study.
{"title":"Study of the optimum number of radiating elements for different portable devices operating in a MIMO system","authors":"O. Gago, L. Gonzalez, R. Eickhoff","doi":"10.1109/EW.2009.5357996","DOIUrl":"https://doi.org/10.1109/EW.2009.5357996","url":null,"abstract":"In this paper it is presented a study of the optimum number of radiating elements in a MIMO array for different portable devices working in the 5.6 GHz band. The array configurations are formed using a Vivaldi antenna as radiating element. This study tries to clarify how many elements are possible to allocate in the different form factors to achieve the best possible effective diversity gain (EDG). Laptop, PDA and PCMCIA are the form factors that are used in this study.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117171949","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}
High peak to average power ratio (PAPR) is a main area of concern in multi-carrier communications as in orthogonal frequency division multiplexing (OFDM) modulated transmission. Several techniques have been devised to reduce the PAPR of the OFDM signal. One of these PAPR reduction techniques is based on peak reducing carriers (PRC) concept where a set of sub-carriers is not used to transmit information but to reduce the temporal signal's peak. There exist different methods to generate the peak reducing carriers like geometric method, gradient method and second order cone programming (SOCP) based optimization method. This paper compares the performance of these three PRC methods for a wireless local area network (WiLAN) system in terms of PAPR reduction capabilities and computational complexities while justifying that neither in-band nor out-of-band interference is generated upon the application of these methods. For an IEEE 802.11g standard, it is found that, on average, SOCP reduces ¿ 2.5 dB more PAPR than geometric method but its complexity is 18 times the complexity of geometric method. While gradient method lies in between these two methods regarding performance and complexity criteria, this paper presents a trade-off between PAPR reduction performance and complexity for three different PRC implementation schemes.
{"title":"Performance comparison of PRC based PAPR reduction schemes for WiLAN Systems","authors":"S. Hussain, D. Guel, Y. Louét, J. Palicot","doi":"10.1109/EW.2009.5358005","DOIUrl":"https://doi.org/10.1109/EW.2009.5358005","url":null,"abstract":"High peak to average power ratio (PAPR) is a main area of concern in multi-carrier communications as in orthogonal frequency division multiplexing (OFDM) modulated transmission. Several techniques have been devised to reduce the PAPR of the OFDM signal. One of these PAPR reduction techniques is based on peak reducing carriers (PRC) concept where a set of sub-carriers is not used to transmit information but to reduce the temporal signal's peak. There exist different methods to generate the peak reducing carriers like geometric method, gradient method and second order cone programming (SOCP) based optimization method. This paper compares the performance of these three PRC methods for a wireless local area network (WiLAN) system in terms of PAPR reduction capabilities and computational complexities while justifying that neither in-band nor out-of-band interference is generated upon the application of these methods. For an IEEE 802.11g standard, it is found that, on average, SOCP reduces ¿ 2.5 dB more PAPR than geometric method but its complexity is 18 times the complexity of geometric method. While gradient method lies in between these two methods regarding performance and complexity criteria, this paper presents a trade-off between PAPR reduction performance and complexity for three different PRC implementation schemes.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134117735","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}
D. Bultmann, M. Muhleisen, K. Klagges, M. Schinnenburg
This paper presents the open Wireless Network Simulator (openWNS). This simulation tool was developed in the last 5 years at the department of Communication Networks (ComNets) at RWTH Aachen University and has been released as open source software recently. openWNS is a dynamic event driven system level simulation platform that allows for investigation of dynamic protocol behaviour in multi-cellular scenarios with detailed interference modeling. The simulation platform follows a modular design down to protocol building blocks, which makes it possible to rapidly modify the implemented protocol stacks. openWNS currently includes models from physical to application layer. The protocol modules for IEEE 802.16m and IEEE 802.11n-draft are probably the most interesting for the wireless research community.
{"title":"OpenWNS - open Wireless Network Simulator","authors":"D. Bultmann, M. Muhleisen, K. Klagges, M. Schinnenburg","doi":"10.1109/EW.2009.5357966","DOIUrl":"https://doi.org/10.1109/EW.2009.5357966","url":null,"abstract":"This paper presents the open Wireless Network Simulator (openWNS). This simulation tool was developed in the last 5 years at the department of Communication Networks (ComNets) at RWTH Aachen University and has been released as open source software recently. openWNS is a dynamic event driven system level simulation platform that allows for investigation of dynamic protocol behaviour in multi-cellular scenarios with detailed interference modeling. The simulation platform follows a modular design down to protocol building blocks, which makes it possible to rapidly modify the implemented protocol stacks. openWNS currently includes models from physical to application layer. The protocol modules for IEEE 802.16m and IEEE 802.11n-draft are probably the most interesting for the wireless research community.","PeriodicalId":412079,"journal":{"name":"2009 European Wireless Conference","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128889549","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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