The Experts below are selected from a list of 4197 Experts worldwide ranked by ideXlab platform
Bernhard Walke - One of the best experts on this subject based on the ideXlab platform.
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theoretical analysis of Saturation Throughput in mu dcf
Vehicular Technology Conference, 2008Co-Authors: J Mirkovic, Bernhard WalkeAbstract:In this paper, the calculation of Saturation Throughput for previously proposed multi-user - distributed coordination function (MU-DCF) is presented. MU-DCF is an IEEE 802.11 based protocol that supports multi-user (MU)-multiple input-multiple output (MIMO) transmissions. The analysis is for two extreme case scenarios: access point (AP) downlink in a hotspot scenario, and fully interconnected network. Special attention is payed on the statistical properties of traffic sources, since in MU-DCF networks they have strong impact on performance. In addition, the difference in performance between MU and single-user (SU) transmission strategies is evaluated, pointing out to the tradeoff between delay and Throughput.
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VTC Spring - Theoretical Analysis of Saturation Throughput in MU-DCF
VTC Spring 2008 - IEEE Vehicular Technology Conference, 2008Co-Authors: J Mirkovic, Bernhard WalkeAbstract:In this paper, the calculation of Saturation Throughput for previously proposed multi-user - distributed coordination function (MU-DCF) is presented. MU-DCF is an IEEE 802.11 based protocol that supports multi-user (MU)-multiple input-multiple output (MIMO) transmissions. The analysis is for two extreme case scenarios: access point (AP) downlink in a hotspot scenario, and fully interconnected network. Special attention is payed on the statistical properties of traffic sources, since in MU-DCF networks they have strong impact on performance. In addition, the difference in performance between MU and single-user (SU) transmission strategies is evaluated, pointing out to the tradeoff between delay and Throughput.
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ieee 802 11e 802 11k wireless lan spectrum awareness for distributed resource sharing
Wireless Communications and Mobile Computing, 2004Co-Authors: Stefan Mangold, Zhun Zhong, Guido R Hiertz, Bernhard WalkeAbstract:Coordinating priorities in wireless medium access is difficult when radio networks operate with contention-based medium access. Contention-based medium access protocols such as listen-before-talk are widely employed today, and for example used in the popular IEEE 802.11 protocol. Contention-based protocols are used for wireless communication in unreliable radio environments such as the unlicensed frequency bands with their typically irregular and unpredictable interferences. However, to support time-bounded traffic with a certain quality of service (QoS) support is extremely difficult, because it requires the knowledge of how aggressive other radio stations, which also contend for radio resources, access the medium. In this contribution, we discuss a new measurement in the IEEE 802.11k draft standard, together with the IEEE 802.11e draft standard for coordinating priorities. By combining the two extensions of IEEE 802.11, we develop an algorithm that allows radio stations to estimate the achievable Throughput per radio station (the Saturation Throughput) in the presence of other radio stations. Our algorithm further allows predicting the Saturation Throughput per radio station in the presence of other non-802.11 radio networks, because it only relies on the information about how the medium is used by other stations, i.e. for what duration other stations have to sense the medium as idle before initiating transmissions. The algorithm does not require knowledge about the contention-parameters (like, e.g. minimum contention window sizes) used by other radio stations, and only relies on medium sensing information. For this reason, we refer to spectrum awareness in this work. We modify an existing model that was originally developed for calculating the Saturation Throughput in IEEE 802.11, to calculate the Saturation Throughput for IEEE 802.11e with one single priority. We then describe a new measurement, which is part of the IEEE 802.11k draft standard. The measurement provides information about medium access probabilities of other radio stations per contention window slots. These probabilities provide the information about how aggressive the medium is utilized by other stations. The probabilities are used in our model for approximating the Saturation Throughput per station and priority in the presence of other radio stations. As a result, with the help of the new model, a radio station is able to estimate its own expected Saturation Throughput. The comparison of the model with stochastic simulation stations indicates that our model approximates the Saturation Throughput per station and priority sufficiently in many scenarios, and hence allows to predict expected Saturation Throughputs per radio station. Copyright © 2004 John Wiley & Sons, Ltd.
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IEEE 802.11e/802.11k wireless LAN: spectrum awareness for distributed resource sharing: Research Articles
2004Co-Authors: Stefan Mangold, Zhun Zhong, Guido R Hiertz, Bernhard WalkeAbstract:Coordinating priorities in wireless medium access is difficult when radio networks operate with contention-based medium access. Contention-based medium access protocols such as listen-before-talk are widely employed today, and for example used in the popular IEEE 802.11 protocol. Contention-based protocols are used for wireless communication in unreliable radio environments such as the unlicensed frequency bands with their typically irregular and unpredictable interferences. However, to support time-bounded traffic with a certain quality of service (QoS) support is extremely difficult, because it requires the knowledge of how aggressive other radio stations, which also contend for radio resources, access the medium. In this contribution, we discuss a new measurement in the IEEE 802.11k draft standard, together with the IEEE 802.11e draft standard for coordinating priorities. By combining the two extensions of IEEE 802.11, we develop an algorithm that allows radio stations to estimate the achievable Throughput per radio station (the Saturation Throughput) in the presence of other radio stations. Our algorithm further allows predicting the Saturation Throughput per radio station in the presence of other non-802.11 radio networks, because it only relies on the information about how the medium is used by other stations, i.e. for what duration other stations have to sense the medium as idle before initiating transmissions. The algorithm does not require knowledge about the contention-parameters (like, e.g. minimum contention window sizes) used by other radio stations, and only relies on medium sensing information. For this reason, we refer to spectrum awareness in this work. We modify an existing model that was originally developed for calculating the Saturation Throughput in IEEE 802.11, to calculate the Saturation Throughput for IEEE 802.11e with one single priority. We then describe a new measurement, which is part of the IEEE 802.11k draft standard. The measurement provides information about medium access probabilities of other radio stations per contention window slots. These probabilities provide the information about how aggressive the medium is utilized by other stations. The probabilities are used in our model for approximating the Saturation Throughput per station and priority in the presence of other radio stations. As a result, with the help of the new model, a radio station is able to estimate its own expected Saturation Throughput. The comparison of the model with stochastic simulation stations indicates that our model approximates the Saturation Throughput per station and priority sufficiently in many scenarios, and hence allows to predict expected Saturation Throughputs per radio station. Copyright © 2004 John Wiley & Sons, Ltd.
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IEEE 802.11e/802.11k wireless LAN: spectrum awareness for distributed resource sharing
Wireless Communications and Mobile Computing, 2004Co-Authors: Stefan Mangold, Zhun Zhong, Guido R Hiertz, Bernhard WalkeAbstract:Coordinating priorities in wireless medium access is difficult when radio networks operate with contention-based medium access. Contention-based medium access protocols such as listen-before-talk are widely employed today, and for example used in the popular IEEE 802.11 protocol. Contention-based protocols are used for wireless communication in unreliable radio environments such as the unlicensed frequency bands with their typically irregular and unpredictable interferences. However, to support time-bounded traffic with a certain quality of service (QoS) support is extremely difficult, because it requires the knowledge of how aggressive other radio stations, which also contend for radio resources, access the medium. In this contribution, we discuss a new measurement in the IEEE 802.11k draft standard, together with the IEEE 802.11e draft standard for coordinating priorities. By combining the two extensions of IEEE 802.11, we develop an algorithm that allows radio stations to estimate the achievable Throughput per radio station (the Saturation Throughput) in the presence of other radio stations. Our algorithm further allows predicting the Saturation Throughput per radio station in the presence of other non-802.11 radio networks, because it only relies on the information about how the medium is used by other stations, i.e. for what duration other stations have to sense the medium as idle before initiating transmissions. The algorithm does not require knowledge about the contention-parameters (like, e.g. minimum contention window sizes) used by other radio stations, and only relies on medium sensing information. For this reason, we refer to spectrum awareness in this work. We modify an existing model that was originally developed for calculating the Saturation Throughput in IEEE 802.11, to calculate the Saturation Throughput for IEEE 802.11e with one single priority. We then describe a new measurement, which is part of the IEEE 802.11k draft standard. The measurement provides information about medium access probabilities of other radio stations per contention window slots. These probabilities provide the information about how aggressive the medium is utilized by other stations. The probabilities are used in our model for approximating the Saturation Throughput per station and priority in the presence of other radio stations. As a result, with the help of the new model, a radio station is able to estimate its own expected Saturation Throughput. The comparison of the model with stochastic simulation stations indicates that our model approximates the Saturation Throughput per station and priority sufficiently in many scenarios, and hence allows to predict expected Saturation Throughputs per radio station. Copyright © 2004 John Wiley & Sons, Ltd.
Farid Ashtiani - One of the best experts on this subject based on the ideXlab platform.
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Analytical Evaluation of Saturation Throughput of a Cognitive WLAN Overlaid on a Time-Scheduled OFDMA Network
IEEE Transactions on Mobile Computing, 2017Co-Authors: Parisa Rahimzadeh, Farid AshtianiAbstract:In this paper, we analyze the Saturation Throughput of a cognitive WLAN overlaid on a primary OFDMA TDD network (e.g., LTE or WiMAX). In this scenario, after the contention among the secondary nodes, the winner node transmits its data packet in the empty resource blocks (RBs) of downlink and uplink subframes of the primary network. Regarding the OFDMA structure as well as time-scheduled resources in the primary network, the time duration of opportunities for the secondary network does not follow simple exponential on-off pattern. To model the dynamic behavior of opportunities for secondary nodes as well as contentions to exploit the opportunities, we propose an analytical model comprised of a discrete-time Markov chain and two inter-related open multi-class queueing networks (QNs). The effects of the random number of empty resource blocks at different frames as the result of random amount of download and upload data, random packet transmission time at WLAN, the dependency of the number of empty RBs at consecutive frames, and the details of 802.11 MAC protocol are included in our analytical approach. We include different resource allocations in the primary network in our analysis. Simulation results confirm the accuracy of our analytical approach in different conditions.
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analysis of the downlink Saturation Throughput of an asymmetric ieee 802 11n based wlan
International Conference on Communications, 2016Co-Authors: Mohammad Soleymani, Behrouz Maham, Farid AshtianiAbstract:Frame aggregation (FA) mechanisms improve the Throughput of WLANs. In this paper, the effect of the FA mechanism on the Throughput of wireless local area networks (WLANs) has been investigated. To this end, we propose an analytical model in order to analyze an IEEE 802.11n network comprised of an access point (AP) and several conventional nodes (CNs), all in the coverage area of each other. With respect to the heavier download traffic compared to the upload one, in our scenario, only the AP uses an FA mechanism and the other nodes use the basic IEEE 802.11 standard. In our proposed analytical model, the maximum downlink (DL) Throughput is derived. Regarding the asymmetry among nodes, our analytical model consists of two different queueing networks: one for the AP and the other one for CNs. We verify the accuracy of our analytical results by simulations, i.e., less than 5% mismatch between the analytical and simulation results. We show that there is a tradeoff between the DL Saturation Throughput and performance of CNs. In other words, the FA improves the AP Saturation Throughput at the cost of a little degradation of the performance for CNs.
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ICC - Analysis of the downlink Saturation Throughput of an asymmetric IEEE 802.11n-based WLAN
2016 IEEE International Conference on Communications (ICC), 2016Co-Authors: Mohammad Soleymani, Behrouz Maham, Farid AshtianiAbstract:Frame aggregation (FA) mechanisms improve the Throughput of WLANs. In this paper, the effect of the FA mechanism on the Throughput of wireless local area networks (WLANs) has been investigated. To this end, we propose an analytical model in order to analyze an IEEE 802.11n network comprised of an access point (AP) and several conventional nodes (CNs), all in the coverage area of each other. With respect to the heavier download traffic compared to the upload one, in our scenario, only the AP uses an FA mechanism and the other nodes use the basic IEEE 802.11 standard. In our proposed analytical model, the maximum downlink (DL) Throughput is derived. Regarding the asymmetry among nodes, our analytical model consists of two different queueing networks: one for the AP and the other one for CNs. We verify the accuracy of our analytical results by simulations, i.e., less than 5% mismatch between the analytical and simulation results. We show that there is a tradeoff between the DL Saturation Throughput and performance of CNs. In other words, the FA improves the AP Saturation Throughput at the cost of a little degradation of the performance for CNs.
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Analytical Evaluation of Saturation Throughput of a Cognitive 802.11-based WLAN Overlaid on a WiMAX-TDD Network.
arXiv: Networking and Internet Architecture, 2014Co-Authors: Parisa Rahimzadeh, Farid AshtianiAbstract:This paper analyzes the Saturation Throughput of a cognitive single hop WLAN overlaid on a primary IEEE 802.16e TDD WiMAX network. After the contention among the secondary nodes, the winner node transmits its data packet in the empty slots of downlink subframes of WiMAX. Regarding the OFDMA structure as well as time-scheduled resources in WiMAX, the time duration of opportunities for the secondary network does not follow simple exponential on-off pattern. To model the dynamic behavior of opportunities for secondary nodes as well as contentions to exploit the opportunities, we propose an analytical model comprised of a discrete-time Markov chain and two inter-related open multi-class queueing networks. The effects of random number of empty slots at different frames as the result of random amount of download data, random packet transmission time at WLAN due to random opportunities in different frames, the dependency of the number of empty slots at consecutive WiMAX frames, and the details of 802.11 MAC protocol are included in our analytical approach. We compare the effect of two resource allocations, i.e., horizontal and vertical striping on the Saturation Throughput of the cognitive WLAN. Simulation results confirm the accuracy of our analytical approach in different conditions.
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Saturation Throughput analysis of a cognitive ieee 802 11 based wlan overlaid on an ieee 802 16e wimax
Personal Indoor and Mobile Radio Communications, 2012Co-Authors: Parisa Rahimzadeh, Masoumeh Moradian, Farid AshtianiAbstract:In this paper, we focus on a cognitive network scenario, comprised of a WLAN overlaid on a network with time-scheduled primary users. WiMAX is an example of such primary networks. For time-scheduled primary users simple On-Off traffic model with exponential durations is not valid anymore. In this scenario, the cognitive nodes (CNs) hear downlink map (DL-MAP) and thus, know the frequency and time locations of all allocated slots at each frame. Then, cognitive nodes contend with each other in order to transmit their fixed size packets based on IEEE 802.11 MAC protocol. Since the number of empty slots at each frame is variable each packet transmission in cognitive network prolongs a random number of frames. By mapping the status of each CN on an open queueing network, including the details of the contention status with the other CNs as well as the statistical distribution of empty slots we are able to derive the Saturation Throughput of the cognitive WLAN. Finally, we derive the Saturation Throughput of cognitive network versus the number of CNs as well as the packet arrival rate at WiMAX in downlink direction and confirm our analytical results by simulation.
Sean Mcgrath - One of the best experts on this subject based on the ideXlab platform.
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Saturation Throughput analysis of multiband ofdm ultra wideband networks
Broadband Communications Networks and Systems, 2008Co-Authors: Liaoyuan Zeng, Eduardo Cano, Sean McgrathAbstract:The Saturation Throughput analysis of the prioritized contention access (PCA) of the WiMedia Ultra Wideband (UWB) standard is presented in this paper. In the WiMedia standard, the Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) is used as the basic physical scheme. An in-depth Bit Error Rate (BER) performance analysis of the MB-OFDM UWB system using IEEE 802.15.3a channel models is conducted to aid the Throughput analysis. The PCA Throughput performance analysis is carried out by extending an original Enhanced Distributed Contention Access (EDCA) model for 802.11e into the MB-OFDM UWB protocol. The extended model considers the effects of the bit error rate, the transmission opportunity limits, and the uniqueness of WiMedia MAC timing structure. The results illustrate that the station Saturation Throughput of the PCA scheme is sensitive to the frame payload length, and there exists an optimal frame payload length that maximizes the Saturation Throughput. The results also show that the Saturation Throughput of the Access Category (AC) with higher priority outperforms the lower prioritized AC under all types of BER conditions.
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BROADNETS - Saturation Throughput analysis of Multiband-OFDM ultra wideband networks
2008 5th International Conference on Broadband Communications Networks and Systems, 2008Co-Authors: Liaoyuan Zeng, Eduardo Cano, Sean McgrathAbstract:The Saturation Throughput analysis of the prioritized contention access (PCA) of the WiMedia Ultra Wideband (UWB) standard is presented in this paper. In the WiMedia standard, the Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) is used as the basic physical scheme. An in-depth Bit Error Rate (BER) performance analysis of the MB-OFDM UWB system using IEEE 802.15.3a channel models is conducted to aid the Throughput analysis. The PCA Throughput performance analysis is carried out by extending an original Enhanced Distributed Contention Access (EDCA) model for 802.11e into the MB-OFDM UWB protocol. The extended model considers the effects of the bit error rate, the transmission opportunity limits, and the uniqueness of WiMedia MAC timing structure. The results illustrate that the station Saturation Throughput of the PCA scheme is sensitive to the frame payload length, and there exists an optimal frame payload length that maximizes the Saturation Throughput. The results also show that the Saturation Throughput of the Access Category (AC) with higher priority outperforms the lower prioritized AC under all types of BER conditions.
Keping Long - One of the best experts on this subject based on the ideXlab platform.
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supporting service differentiation and maximizing system Saturation Throughput a contradictory in ieee 802 11e wlan
International Conference on Communications, 2008Co-Authors: Qianbin Chen, Chonggang Wang, Keping LongAbstract:While most existing work focuses separately on how to improve WLAN Saturation throughout and how to provide differentiated service, few attention is put to study their relationship. In this paper, we investigate the impact of service differentiation on Saturation Throughput maximization in IEEE 802.11e WLANs and theoretically prove that it is contradictory and impossible to achieve both of them simultaneously. In other words, Saturation Throughput is maximized without service differentiation or service differentiation reduces the maximal achievable Saturation Throughput more or less.
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ICC - Supporting Service Differentiation and Maximizing System Saturation Throughput: A Contradictory in IEEE 802.11e WLAN
2008 IEEE International Conference on Communications, 2008Co-Authors: Qianbin Chen, Chonggang Wang, Keping LongAbstract:While most existing work focuses separately on how to improve WLAN Saturation throughout and how to provide differentiated service, few attention is put to study their relationship. In this paper, we investigate the impact of service differentiation on Saturation Throughput maximization in IEEE 802.11e WLANs and theoretically prove that it is contradictory and impossible to achieve both of them simultaneously. In other words, Saturation Throughput is maximized without service differentiation or service differentiation reduces the maximal achievable Saturation Throughput more or less.
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Defining and maximizing PPT—a novel performance parameter for IEEE 802.11 DCF
International Journal of Communication Systems, 2006Co-Authors: Keping Long, Wei-liang ZhaoAbstract:Much research has been conducted on Saturation Throughput of IEEE802.11 DCF, and has led to some improvement. But increasing the successful transmission probability of packet is also important for saving stations' battery energy and decreasing the packet delay. In this paper, we define a new performance parameter, named Product of successful transmission Probability and Saturation Throughput (PPT), for 802.11 DCF, which binds successful transmission probability and Saturation Throughput together. An analysis is given to maximize PPT. An expression of optimal minimum contention windows (CWmin) is obtained analytically for maximizing PPT. For simplicity, we give a name DCF-PPT to the 802.11 DCF that sets its CWmin according to this expression. The performance of DCF-PPT is simulated with different stations in terms of Saturation Throughput, successful transmission probability and PPT. The simulation results indicate that, compared to 802.11 DCF, DCF-PPT can significantly increase the PPT and successful transmission probability (about 0.95) on condition that the Saturation Throughput is not decreased. Copyright © 2006 John Wiley & Sons, Ltd.
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Defining and maximizing PPT—a novel performance parameter for IEEE 802.11 DCF: Research Articles
International Journal of Communication Systems, 2006Co-Authors: Keping Long, Wei-liang ZhaoAbstract:Much research has been conducted on Saturation Throughput of IEEE802.11 DCF, and has led to some improvement. But increasing the successful transmission probability of packet is also important for saving stations' battery energy and decreasing the packet delay. In this paper, we define a new performance parameter, named Product of successful transmission Probability and Saturation Throughput (PPT), for 802.11 DCF, which binds successful transmission probability and Saturation Throughput together. An analysis is given to maximize PPT. An expression of optimal minimum contention windows (CWmin) is obtained analytically for maximizing PPT. For simplicity, we give a name DCF-PPT to the 802.11 DCF that sets its CWmin according to this expression. The performance of DCF-PPT is simulated with different stations in terms of Saturation Throughput, successful transmission probability and PPT. The simulation results indicate that, compared to 802.11 DCF, DCF-PPT can significantly increase the PPT and successful transmission probability (about 0.95) on condition that the Saturation Throughput is not decreased. Copyright © 2006 John Wiley & Sons, Ltd.
Mao Xingjun - One of the best experts on this subject based on the ideXlab platform.
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Saturation Throughput Analysis of Wireless Ad Hoc Networks Under Influence of Capture Effect
Computer Engineering, 2007Co-Authors: Mao XingjunAbstract:The influence of capture effect on Saturation Throughput of distributed wireless ad hoc network is investigated.The capture probabilit y of ad hoc networks whose nodes are uniformly distributed is obtained.With certain capture probability,the Saturation Throughput of 802.11 DCF is also derived.
