Within the last few years, prevalence and importance of wireless networks increased significantly. Especially, wireless mesh networks received a lot of attention in both academic research and commercial deployments. Wireless mesh networks are characterized by wireless multi-hop connectivity and facilitate a simple and cost-effective establishment of wireless networks while providing large coverage areas. The ongoing standardization of IEEE 802.11s WLAN Mesh Networking defines the Hybrid Wireless Mesh Protocol (HWMP) for link layer path selection. This protocol offers various modes of operation that are suitable for different environments. In this paper, a detailed simulative evaluation of these modes allows for conclusions about their performance and suitability for specific environments.
{"title":"Simulative analysis of the Hybrid Wireless Mesh Protocol (HWMP)","authors":"M. Cornils, Michael Bahr, Thomas Gamer","doi":"10.1109/EW.2010.5483486","DOIUrl":"https://doi.org/10.1109/EW.2010.5483486","url":null,"abstract":"Within the last few years, prevalence and importance of wireless networks increased significantly. Especially, wireless mesh networks received a lot of attention in both academic research and commercial deployments. Wireless mesh networks are characterized by wireless multi-hop connectivity and facilitate a simple and cost-effective establishment of wireless networks while providing large coverage areas. The ongoing standardization of IEEE 802.11s WLAN Mesh Networking defines the Hybrid Wireless Mesh Protocol (HWMP) for link layer path selection. This protocol offers various modes of operation that are suitable for different environments. In this paper, a detailed simulative evaluation of these modes allows for conclusions about their performance and suitability for specific environments.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126455619","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, some new studies about LT and Raptor codes are presented. Upper and lower bounds on the asymptotic average error probability are derived and they appear quite tight to predict the performance in the error floor region. This study allows to underline the existing trade-off between the asymptotic overhead and the performance in the error floor region. Then, we propose a method to optimize the precode profile for a given LT distribution using a mixture of Gaussian channels.
{"title":"Some new results on LT and Raptor codes","authors":"A. Venkiah, C. Poulliat","doi":"10.1109/EW.2010.5483534","DOIUrl":"https://doi.org/10.1109/EW.2010.5483534","url":null,"abstract":"In this paper, some new studies about LT and Raptor codes are presented. Upper and lower bounds on the asymptotic average error probability are derived and they appear quite tight to predict the performance in the error floor region. This study allows to underline the existing trade-off between the asymptotic overhead and the performance in the error floor region. Then, we propose a method to optimize the precode profile for a given LT distribution using a mixture of Gaussian channels.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125929105","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}
Activity patterns of primary users have significant influence on the opportunities for secondary use of spectrum. In this paper we explore this impact in terms of spatial spectrum reuse opportunities. More specifically, we model the primary user activity as a Semi-Markov ON/OFF process with varying distributions of holding times of ON and OFF states. We have used realistic holding time distributions obtained from extensive measurement campaigns. These activity patterns are combined with a collection of primary user transmitter locations, based on a real deployed cellular network. Based on these, we study the impact of activity model parameters on opportunities of spatial spectrum reuse. The results indicate that for the scenarios studied here the overall duty cycle defined by the activity pattern plays the key role also in determining spatial spectrum opportunities. We also discuss applications of the obtained results, including development of lightweight models for occurrences of spectrum opportunities over both time and space.
{"title":"Impact of primary user activity patterns on spatial spectrum reuse opportunities","authors":"J. Riihijarvi, J. Nasreddine, P. Mähönen","doi":"10.1109/EW.2010.5483445","DOIUrl":"https://doi.org/10.1109/EW.2010.5483445","url":null,"abstract":"Activity patterns of primary users have significant influence on the opportunities for secondary use of spectrum. In this paper we explore this impact in terms of spatial spectrum reuse opportunities. More specifically, we model the primary user activity as a Semi-Markov ON/OFF process with varying distributions of holding times of ON and OFF states. We have used realistic holding time distributions obtained from extensive measurement campaigns. These activity patterns are combined with a collection of primary user transmitter locations, based on a real deployed cellular network. Based on these, we study the impact of activity model parameters on opportunities of spatial spectrum reuse. The results indicate that for the scenarios studied here the overall duty cycle defined by the activity pattern plays the key role also in determining spatial spectrum opportunities. We also discuss applications of the obtained results, including development of lightweight models for occurrences of spectrum opportunities over both time and space.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134060384","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 investigates the bandwidth efficiency of packet based mobile backhaul in case of low rate, delay sensitive voice service. Evolved HSPA is a fully packet based mobile technology where the voice service is VoIP based. VoIP sources generate small packets periodically. The overhead on these packets is significant; it even exceeds the useful payload, causing efficiency problems on the mobile backhaul where bandwidth is still a scarce resource. A possible way to improve the efficiency of the voice service is to aggregate multiple voice packets into a single transport frame, a technique that reduces the relative overhead. This paper provides an overview of the available aggregation methods referred to as bundling and multiplexing. The performance of these solutions and their impact on the QoS of the voice service is investigated with simulations. Results show that if the backhaul is the bottleneck, the maximum number of VoIP connections that can be served jumps by up to 60%.
{"title":"Bundling and multiplexing in packet based mobile backhaul","authors":"Árpád Drozdy, Zoltán Vincze, C. Vulkán","doi":"10.1109/EW.2010.5483443","DOIUrl":"https://doi.org/10.1109/EW.2010.5483443","url":null,"abstract":"This paper investigates the bandwidth efficiency of packet based mobile backhaul in case of low rate, delay sensitive voice service. Evolved HSPA is a fully packet based mobile technology where the voice service is VoIP based. VoIP sources generate small packets periodically. The overhead on these packets is significant; it even exceeds the useful payload, causing efficiency problems on the mobile backhaul where bandwidth is still a scarce resource. A possible way to improve the efficiency of the voice service is to aggregate multiple voice packets into a single transport frame, a technique that reduces the relative overhead. This paper provides an overview of the available aggregation methods referred to as bundling and multiplexing. The performance of these solutions and their impact on the QoS of the voice service is investigated with simulations. Results show that if the backhaul is the bottleneck, the maximum number of VoIP connections that can be served jumps by up to 60%.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131144788","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 a general soft-based synchronization technique for continuous phase modulations (CPM) is presented. In particular two soft carrier phase estimation algorithms are derived, being the phase the parameter that shows the lower implementation complexity. These algorithms exploit the trellis structure inherent in the modulator of CPM signals and make use of a symbol-based BCJR, developed in an ad-hoc way for an uncoded CPM signal. The algorithms are blind and are designed to work with all CPM family. Simulation results for the soft carrier phase estimation are presented in terms of Root Mean Square Estimation Error (RMSEE). The modified Cramer-Rao bound (MCRB) is also shown for reference. RMSEE of soft recovery approach is very close to MCRB for all the examined formats.
{"title":"Soft carrier phase recovery for continuous phase modulations","authors":"Marilena Maiolo, G. Boccolini, M. Luise","doi":"10.1109/EW.2010.5483462","DOIUrl":"https://doi.org/10.1109/EW.2010.5483462","url":null,"abstract":"In this paper a general soft-based synchronization technique for continuous phase modulations (CPM) is presented. In particular two soft carrier phase estimation algorithms are derived, being the phase the parameter that shows the lower implementation complexity. These algorithms exploit the trellis structure inherent in the modulator of CPM signals and make use of a symbol-based BCJR, developed in an ad-hoc way for an uncoded CPM signal. The algorithms are blind and are designed to work with all CPM family. Simulation results for the soft carrier phase estimation are presented in terms of Root Mean Square Estimation Error (RMSEE). The modified Cramer-Rao bound (MCRB) is also shown for reference. RMSEE of soft recovery approach is very close to MCRB for all the examined formats.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114065983","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 distributed beamforming algorithm is proposed for the two-user multiple-input single-output (MISO) interference channel (IFC). The algorithm is iterative and uses as bargaining value the interference that each transmitter generates towards the receiver of the other user. It enables cooperation among the transmitters in order to increase both users' rates by lowering the overall interference. In every iteration, as long as both rates keep on increasing, the transmitters mutually decrease the generated interference. They choose their beamforming vectors distributively, solving the constrained optimization problem of maximizing the useful signal power for a given level of generated interference. The algorithm is equally applicable when the transmitters have either instantaneous or statistical channel state information (CSI). The difference is that the core optimization problem is solved in closed-form for instantaneous CSI, whereas for statistical CSI an efficient solution is found numerically via semidefinite programming. The outcome of the proposed algorithm is approximately Pareto-optimal. Extensive numerical illustrations are provided, comparing the proposed solution to the Nash equilibrium, zero-forcing, Nash bargaining, and maximum sum-rate operating points.
{"title":"Cooperative beamforming for the MISO interference channel","authors":"J. Lindblom, E. Karipidis","doi":"10.1109/EW.2010.5483473","DOIUrl":"https://doi.org/10.1109/EW.2010.5483473","url":null,"abstract":"A distributed beamforming algorithm is proposed for the two-user multiple-input single-output (MISO) interference channel (IFC). The algorithm is iterative and uses as bargaining value the interference that each transmitter generates towards the receiver of the other user. It enables cooperation among the transmitters in order to increase both users' rates by lowering the overall interference. In every iteration, as long as both rates keep on increasing, the transmitters mutually decrease the generated interference. They choose their beamforming vectors distributively, solving the constrained optimization problem of maximizing the useful signal power for a given level of generated interference. The algorithm is equally applicable when the transmitters have either instantaneous or statistical channel state information (CSI). The difference is that the core optimization problem is solved in closed-form for instantaneous CSI, whereas for statistical CSI an efficient solution is found numerically via semidefinite programming. The outcome of the proposed algorithm is approximately Pareto-optimal. Extensive numerical illustrations are provided, comparing the proposed solution to the Nash equilibrium, zero-forcing, Nash bargaining, and maximum sum-rate operating points.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121268476","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}
Benoit Pijcke, M. Zwingelstein-Colin, M. Gazalet, F. Coudoux
In this paper, we analyse the interference power in a typical wireless cellular network. We provide an analytical approximation for the probability density function of the interference power, which does not depend on the user's position, and which is validated by simulation. The key idea of the approximation results from our observation that the variations of the pathloss between a user and an interfering base station (due to the variations of the user's position within its cell) are negligible in comparison with the multipath fading variations. The results obtained in this paper may be used to greatly simplify the analysis of some network optimization problems (inter-cell interference coordination, capacity optimization…), as well as system level simulations of wireless cellular networks.
{"title":"On modeling the downlink inter-cell interference power in wireless cellular networks","authors":"Benoit Pijcke, M. Zwingelstein-Colin, M. Gazalet, F. Coudoux","doi":"10.1109/EW.2010.5483433","DOIUrl":"https://doi.org/10.1109/EW.2010.5483433","url":null,"abstract":"In this paper, we analyse the interference power in a typical wireless cellular network. We provide an analytical approximation for the probability density function of the interference power, which does not depend on the user's position, and which is validated by simulation. The key idea of the approximation results from our observation that the variations of the pathloss between a user and an interfering base station (due to the variations of the user's position within its cell) are negligible in comparison with the multipath fading variations. The results obtained in this paper may be used to greatly simplify the analysis of some network optimization problems (inter-cell interference coordination, capacity optimization…), as well as system level simulations of wireless cellular networks.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116005390","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 coordinated multicell zero-forcing beamforming (ZFBF) together with downlink scheduling. Optimal scheduling requires a network-wide search through all scheduling combinations which is generally not feasible. To this end we propose a distributed scheduling algorithm. To put the performance in perspective we use single-cell processing (SCP) with optimal scheduling as a reference. Specifically, we derive approximate expressions for the number of users needed to attain the same mean post-scheduling SINR with SCP and ZFBF. We generalize to similar results for the capacity and show that large gains can be obtained with multicell ZFBF.
{"title":"Multicell zero-forcing beamforming and multiuser scheduling","authors":"H. J. Bang","doi":"10.1109/EW.2010.5483498","DOIUrl":"https://doi.org/10.1109/EW.2010.5483498","url":null,"abstract":"In this paper we study coordinated multicell zero-forcing beamforming (ZFBF) together with downlink scheduling. Optimal scheduling requires a network-wide search through all scheduling combinations which is generally not feasible. To this end we propose a distributed scheduling algorithm. To put the performance in perspective we use single-cell processing (SCP) with optimal scheduling as a reference. Specifically, we derive approximate expressions for the number of users needed to attain the same mean post-scheduling SINR with SCP and ZFBF. We generalize to similar results for the capacity and show that large gains can be obtained with multicell ZFBF.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126067413","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}
Recently the realization of Artificial Magnetic Conductors (AMCs) has attracted a great deal of interest among researchers as they can replace perfect electric conductors (PECs) for low profile antennas and other microwave applications. In this paper, the design of ultra thin low profile dipole antenna using AMC ground plane with an overall height of 0.045λ at 3GHz is presented. The AMC ground plane is realized by using low cost planar square split ring resonators (SRRs) printed on a thin PEC backed dielectric substrate. First, the performances of the proposed AMC surface is investigated and then a comparative investigation has been conducted to study the radiation characteristics of dipole antennas closely and parallel above an ideal PEC surface and the proposed AMC structure. Both Ansoft HFSS™ and Ansoft Designer™ have been used to predict the reflection phase stop band of the proposed AMC structure and the dipole antenna characteristics.
{"title":"Low profile dipole antenna design using square SRRs artificial ground plane","authors":"M. Al-Nuaimi","doi":"10.1109/EW.2010.5483416","DOIUrl":"https://doi.org/10.1109/EW.2010.5483416","url":null,"abstract":"Recently the realization of Artificial Magnetic Conductors (AMCs) has attracted a great deal of interest among researchers as they can replace perfect electric conductors (PECs) for low profile antennas and other microwave applications. In this paper, the design of ultra thin low profile dipole antenna using AMC ground plane with an overall height of 0.045λ at 3GHz is presented. The AMC ground plane is realized by using low cost planar square split ring resonators (SRRs) printed on a thin PEC backed dielectric substrate. First, the performances of the proposed AMC surface is investigated and then a comparative investigation has been conducted to study the radiation characteristics of dipole antennas closely and parallel above an ideal PEC surface and the proposed AMC structure. Both Ansoft HFSS™ and Ansoft Designer™ have been used to predict the reflection phase stop band of the proposed AMC structure and the dipole antenna characteristics.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114696971","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}
P. Lahdekorpi, T. Isotalo, K. Kyla-Liuhala, J. Lempiainen
This paper discusses the use of high altitude platforms, HAPs, to provide mobile communication services to on-ground customers. The paper explains the behavior of UMTS radio network in a situation, where the service is being provided by HAP and terrestrial base stations in a disaster scenario. In the disaster scenario, a set of adjacent terrestrial cellular base stations in the middle of the network have been disabled. A HAP station has been launched to the disaster location to provide UMTS service. The possible effects between the HAP and the terrestrial UMTS network are assessed from the system point of view by analyzing the simulation results of the radio interface. The results show that the HAP is able to improve the performance in the radio network by providing UMTS coverage from the HAP station. The HAP station is able to restore the disaster area throughput to the level of 70 % from the original level. However, to achieve good network performance using HAP, careful configuration planning is required. Thus with careless HAP configuration design, the HAP service performance could totally be lost.
{"title":"Replacing terrestrial UMTS coverage by HAP in disaster scenarios","authors":"P. Lahdekorpi, T. Isotalo, K. Kyla-Liuhala, J. Lempiainen","doi":"10.1109/EW.2010.5483388","DOIUrl":"https://doi.org/10.1109/EW.2010.5483388","url":null,"abstract":"This paper discusses the use of high altitude platforms, HAPs, to provide mobile communication services to on-ground customers. The paper explains the behavior of UMTS radio network in a situation, where the service is being provided by HAP and terrestrial base stations in a disaster scenario. In the disaster scenario, a set of adjacent terrestrial cellular base stations in the middle of the network have been disabled. A HAP station has been launched to the disaster location to provide UMTS service. The possible effects between the HAP and the terrestrial UMTS network are assessed from the system point of view by analyzing the simulation results of the radio interface. The results show that the HAP is able to improve the performance in the radio network by providing UMTS coverage from the HAP station. The HAP station is able to restore the disaster area throughput to the level of 70 % from the original level. However, to achieve good network performance using HAP, careful configuration planning is required. Thus with careless HAP configuration design, the HAP service performance could totally be lost.","PeriodicalId":232165,"journal":{"name":"2010 European Wireless Conference (EW)","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121550460","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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