Pub Date : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534954
Konstantin Chomu, L. Gavrilovska
Energy efficiency of Wireless Sensor Networks (WSNs) is highly affected by duration of periods when sensors transmit data. In order to reduce the amount of transmitted bits from each sensor's radio, the basic Data Timed Sending (DTS) method was recently proposed by the authors [1]. Basic DTS addresses the packet size reduction, achieved by eliminating the Data Payload from the data packets or by using the acknowledgment packets. The information about measured values is transferred by choosing appropriate moment (time slot and time window) in the time interval for performing the packet transmission. The position of every time slot corresponds to a particular node and the position of every time window corresponds to a certain value of measured phenomenon. In one time interval each node sends data from one measurement. Since the synchronization is crucial for feasibility of this method, this paper examines the impact of synchronization error. The simulation results show that for the realistic levels of noise, the Linear Regression (LR) synchronization technique offers sufficient accuracy.
{"title":"Synchronization impact on the performance of Data-Timed Sending (DTS) based wireless sensor networks","authors":"Konstantin Chomu, L. Gavrilovska","doi":"10.1109/WOWMOM.2010.5534954","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534954","url":null,"abstract":"Energy efficiency of Wireless Sensor Networks (WSNs) is highly affected by duration of periods when sensors transmit data. In order to reduce the amount of transmitted bits from each sensor's radio, the basic Data Timed Sending (DTS) method was recently proposed by the authors [1]. Basic DTS addresses the packet size reduction, achieved by eliminating the Data Payload from the data packets or by using the acknowledgment packets. The information about measured values is transferred by choosing appropriate moment (time slot and time window) in the time interval for performing the packet transmission. The position of every time slot corresponds to a particular node and the position of every time window corresponds to a certain value of measured phenomenon. In one time interval each node sends data from one measurement. Since the synchronization is crucial for feasibility of this method, this paper examines the impact of synchronization error. The simulation results show that for the realistic levels of noise, the Linear Regression (LR) synchronization technique offers sufficient accuracy.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115095805","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534995
G. Ács, L. Buttyán, László Dóra
In this paper, we address the problem of detecting misbehaving routers in wireless mesh networks and avoiding them when selecting routes. We assume that link-state routing is used, and we essentially propose a reputation system, where trusted gateway nodes compute Node Trust Values for the routers, which are fed back into the system and used in the route selection procedure. The computation of the Node Trust Values is based on packet counters maintained in association with each route and reported to the gateways by the routers in a regular manner. The feedback mechanism is based on limited scope flooding. The received Node Trust Values concerning a given router are aggregated, and the aggregate trust value of the router determines the probability with which that router is kept in the topology graph used for route computation. Hence, less trusted routers are excluded from the topology graph with higher probability, while the route selection still runs on a weighted graph (where the weights are determined by the announced link qualities), and it does not need to be changed. We evaluated the performance of our solution by means of simulations. The results show that our proposed mechanism can detect misbehaving routers reliably, and thanks to the feedback and the exclusion of the accused nodes from the route selection, we can decrease the number of packets dropped due to router misbehavior considerably. At the same time, our mechanism only slightly increases the average route length.
{"title":"Misbehaving router detection in link-state routing for wireless mesh networks","authors":"G. Ács, L. Buttyán, László Dóra","doi":"10.1109/WOWMOM.2010.5534995","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534995","url":null,"abstract":"In this paper, we address the problem of detecting misbehaving routers in wireless mesh networks and avoiding them when selecting routes. We assume that link-state routing is used, and we essentially propose a reputation system, where trusted gateway nodes compute Node Trust Values for the routers, which are fed back into the system and used in the route selection procedure. The computation of the Node Trust Values is based on packet counters maintained in association with each route and reported to the gateways by the routers in a regular manner. The feedback mechanism is based on limited scope flooding. The received Node Trust Values concerning a given router are aggregated, and the aggregate trust value of the router determines the probability with which that router is kept in the topology graph used for route computation. Hence, less trusted routers are excluded from the topology graph with higher probability, while the route selection still runs on a weighted graph (where the weights are determined by the announced link qualities), and it does not need to be changed. We evaluated the performance of our solution by means of simulations. The results show that our proposed mechanism can detect misbehaving routers reliably, and thanks to the feedback and the exclusion of the accused nodes from the route selection, we can decrease the number of packets dropped due to router misbehavior considerably. At the same time, our mechanism only slightly increases the average route length.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122028423","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534918
R. Milocco, S. Boumerdassi
After considering the intrinsically erratic behavior of nodes in mobile networks, mobility prediction has been extensively used to improve the quality of services. Many methods have been proposed, inherited from technologies developed for signal processing and self-learning techniques and/or stochastic methods. Among the latter the Extended Kalman Filter (EKF), using the received power as a measurement, is the most used. However, because the measure is not linear with distance, the EKF loses stability under certain circumstances and must be reset. Moreover, it requires the a priori knowledge of disturbances and measurement noise covariance matrices which are difficult to obtain. In this work, from the non-linear model, we derive a stable time-variant first order auto-regressive and moving average model (ARMA), and propose a prediction mechanism based on the well-known Recursive Prediction Error Method (RPEM) to predict the mobile location and then compare it with (EKF). Simulation results show that RPEM has a lower prediction error variance in most cases and similar in others to that obtained with EKF with the additional advantages that it has guaranteed stability and does not require the a priori knowledge of disturbances and measurement noise covariance matrices as in EKF.
{"title":"Estimation and prediction for tracking trajectories in cellular networks using the recursive prediction error method","authors":"R. Milocco, S. Boumerdassi","doi":"10.1109/WOWMOM.2010.5534918","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534918","url":null,"abstract":"After considering the intrinsically erratic behavior of nodes in mobile networks, mobility prediction has been extensively used to improve the quality of services. Many methods have been proposed, inherited from technologies developed for signal processing and self-learning techniques and/or stochastic methods. Among the latter the Extended Kalman Filter (EKF), using the received power as a measurement, is the most used. However, because the measure is not linear with distance, the EKF loses stability under certain circumstances and must be reset. Moreover, it requires the a priori knowledge of disturbances and measurement noise covariance matrices which are difficult to obtain. In this work, from the non-linear model, we derive a stable time-variant first order auto-regressive and moving average model (ARMA), and propose a prediction mechanism based on the well-known Recursive Prediction Error Method (RPEM) to predict the mobile location and then compare it with (EKF). Simulation results show that RPEM has a lower prediction error variance in most cases and similar in others to that obtained with EKF with the additional advantages that it has guaranteed stability and does not require the a priori knowledge of disturbances and measurement noise covariance matrices as in EKF.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116880360","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534906
M. Heusse, G. Urvoy-Keller, A. Duda, T. Brown
Wireless LANs suffer from performance problems caused by insufficient medium access opportunity given to the access point. Consequently, the downlink buffer fills up, which often leads to packet losses. We propose to address this problem by using a size-based scheduling approach, which is known to favor short flows and the start up of new ones-a very appealing property from the user's perspective as interactive applications and new flows are serviced quickly. Still, size-based scheduling policies have a well-known Achilles heel: large flows can block each other for long periods of time and low rate multimedia transfers may end up with a low priority when their accumulated transferred volume becomes large. To solve the above deficiencies, we propose a new packet scheduling scheme called Least Attained Recent Service (LARS) that applies a temporal decay to the volume of data associated with each flow. In this way, its priority depends more on what has happened recently. With this strategy, LARS can bound the impact of a new arriving flow on ongoing flows, thus limiting lock out durations. It can also efficiently protect low rate multimedia transfers irrespectively of the load conditions.
{"title":"Least attained recent service for packet scheduling over wireless LANs","authors":"M. Heusse, G. Urvoy-Keller, A. Duda, T. Brown","doi":"10.1109/WOWMOM.2010.5534906","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534906","url":null,"abstract":"Wireless LANs suffer from performance problems caused by insufficient medium access opportunity given to the access point. Consequently, the downlink buffer fills up, which often leads to packet losses. We propose to address this problem by using a size-based scheduling approach, which is known to favor short flows and the start up of new ones-a very appealing property from the user's perspective as interactive applications and new flows are serviced quickly. Still, size-based scheduling policies have a well-known Achilles heel: large flows can block each other for long periods of time and low rate multimedia transfers may end up with a low priority when their accumulated transferred volume becomes large. To solve the above deficiencies, we propose a new packet scheduling scheme called Least Attained Recent Service (LARS) that applies a temporal decay to the volume of data associated with each flow. In this way, its priority depends more on what has happened recently. With this strategy, LARS can bound the impact of a new arriving flow on ongoing flows, thus limiting lock out durations. It can also efficiently protect low rate multimedia transfers irrespectively of the load conditions.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128276055","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534912
J. Ku, Y. Ko, Jisun An, Dongman Lee
A social-based routing protocol for opportunistic networks considers the direct delivery as forwarding metrics. By ignoring the indirect delivery through intermediate nodes, it misses chances to find paths that are better in terms of delivery ratio and time. To overcome this limitation, we propose to incorporate transitivity, which considers the indirect delivery through intermediate nodes, as one of the forwarding metrics. We also found that some message forwards do not improve the delivery performance. To reduce the number of these useless forwards, the proposed scheme forwards messages to an encountered node when the increase of total utility value is greater than a threshold. Using a simulator with real world trace data sets, we compare the proposed scheme with the existing protocols, epidemic routing and SimBetTS. Compared with SimBetTS, the proposed scheme increases delivery ratio by 1.5 percent and decreases delay time by 2 percent while reducing overhead by 30 percent.
{"title":"A social transitivity-based data dissemination scheme for opportunistic networks","authors":"J. Ku, Y. Ko, Jisun An, Dongman Lee","doi":"10.1109/WOWMOM.2010.5534912","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534912","url":null,"abstract":"A social-based routing protocol for opportunistic networks considers the direct delivery as forwarding metrics. By ignoring the indirect delivery through intermediate nodes, it misses chances to find paths that are better in terms of delivery ratio and time. To overcome this limitation, we propose to incorporate transitivity, which considers the indirect delivery through intermediate nodes, as one of the forwarding metrics. We also found that some message forwards do not improve the delivery performance. To reduce the number of these useless forwards, the proposed scheme forwards messages to an encountered node when the increase of total utility value is greater than a threshold. Using a simulator with real world trace data sets, we compare the proposed scheme with the existing protocols, epidemic routing and SimBetTS. Compared with SimBetTS, the proposed scheme increases delivery ratio by 1.5 percent and decreases delay time by 2 percent while reducing overhead by 30 percent.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129835978","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534921
Gábor Fodor, S. Sorrentino, M. Johansson, Pablo Soldati
Network multiple input, multiple output (MIMO) systems are built around a broadband backbone network that allows for the fast communication of channel state information (CSI) as well as user data between different base stations. Previous works have shown that multicell channel adaptive (opportunistic) power control can minimize the sum power or maximize the sum rate when the backbone is used for the exchange of CSI in network MIMO systems. In this work we investigate the gains of multicell opportunistic power control under per user fairness constraints when both CSI and user data are shared between multiple sites. We find that multicell opportunistic power control working in concert with uplink joint signal detection is an efficient means both for the capacity and the power control problems that not only minimizes sum power or maximizes overall capacity, but is also able to provide arbitrary level of fairness.
{"title":"On the impact of uplink power control in network MIMO systems with MMSE and SIC receivers","authors":"Gábor Fodor, S. Sorrentino, M. Johansson, Pablo Soldati","doi":"10.1109/WOWMOM.2010.5534921","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534921","url":null,"abstract":"Network multiple input, multiple output (MIMO) systems are built around a broadband backbone network that allows for the fast communication of channel state information (CSI) as well as user data between different base stations. Previous works have shown that multicell channel adaptive (opportunistic) power control can minimize the sum power or maximize the sum rate when the backbone is used for the exchange of CSI in network MIMO systems. In this work we investigate the gains of multicell opportunistic power control under per user fairness constraints when both CSI and user data are shared between multiple sites. We find that multicell opportunistic power control working in concert with uplink joint signal detection is an efficient means both for the capacity and the power control problems that not only minimizes sum power or maximizes overall capacity, but is also able to provide arbitrary level of fairness.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130103111","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534960
E. Bulut, S. Geyik, B. Szymanski
Delay tolerant networks are characterized by the sporadic connectivity between their nodes and therefore the lack of stable end-to-end paths from source to destination. Since the future node connections are mostly unknown in these networks, opportunistic forwarding is used to deliver messages. However, making effective forwarding decisions using only the network characteristics (i.e. average intermeeting time between nodes) extracted from contact history is a challenging problem. Based on the observations about human mobility traces and the findings of previous work, we introduce a new metric called conditional intermeeting time, which computes the average intermeeting time between two nodes relative to a meeting with a third node using only the local knowledge of the past contacts. We then look at the effects of the proposed metric on the shortest path based routing designed for delay tolerant networks. We propose Conditional Shortest Path Routing (CSPR) protocol that routes the messages over conditional shortest paths in which the cost of links between nodes is defined by conditional intermeeting times rather than the conventional intermeeting times. Through trace-driven simulations, we demonstrate that CSPR achieves higher delivery rate and lower end-to-end delay compared to the shortest path based routing protocols that use the conventional intermeeting time as the link metric.
{"title":"Conditional shortest path routing in delay tolerant networks","authors":"E. Bulut, S. Geyik, B. Szymanski","doi":"10.1109/WOWMOM.2010.5534960","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534960","url":null,"abstract":"Delay tolerant networks are characterized by the sporadic connectivity between their nodes and therefore the lack of stable end-to-end paths from source to destination. Since the future node connections are mostly unknown in these networks, opportunistic forwarding is used to deliver messages. However, making effective forwarding decisions using only the network characteristics (i.e. average intermeeting time between nodes) extracted from contact history is a challenging problem. Based on the observations about human mobility traces and the findings of previous work, we introduce a new metric called conditional intermeeting time, which computes the average intermeeting time between two nodes relative to a meeting with a third node using only the local knowledge of the past contacts. We then look at the effects of the proposed metric on the shortest path based routing designed for delay tolerant networks. We propose Conditional Shortest Path Routing (CSPR) protocol that routes the messages over conditional shortest paths in which the cost of links between nodes is defined by conditional intermeeting times rather than the conventional intermeeting times. Through trace-driven simulations, we demonstrate that CSPR achieves higher delivery rate and lower end-to-end delay compared to the shortest path based routing protocols that use the conventional intermeeting time as the link metric.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"160 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132480137","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534926
Sion Scone, I. Phillips
In urban search and rescue (USAR) operations, there is a considerable amount of danger faced by rescuers. The use of mobile robots can alleviate this issue. Coordinating the search effort is made more difficult by the communication issues typically faced in these environments, such that communication is often restricted to line of sight. Since the rescue workers outside of the structure need to know the location of any victims, the task is two parted: 1) to locate the victims (Search Time), and 2) to get this data outside the structure (Delay Time). Communication with the outside is assumed to be performed by a static robot designated as the Command Station. Since it is unlikely that there will be sufficient robots to provide full communications coverage of the area, robots that discover victims are faced with the difficult decision of whether they should continue searching or return with the victim data. We investigate a variety of search techniques and see how the application of biological foraging models can help to streamline the search process, while we have also implemented an opportunistic network to ensure that data are shared whenever robots come within line of sight of each other or the Command Station. We examine this trade-off between performing a search and communicating the results.
{"title":"Trade-off between exploration and reporting victim locations in USAR","authors":"Sion Scone, I. Phillips","doi":"10.1109/WOWMOM.2010.5534926","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534926","url":null,"abstract":"In urban search and rescue (USAR) operations, there is a considerable amount of danger faced by rescuers. The use of mobile robots can alleviate this issue. Coordinating the search effort is made more difficult by the communication issues typically faced in these environments, such that communication is often restricted to line of sight. Since the rescue workers outside of the structure need to know the location of any victims, the task is two parted: 1) to locate the victims (Search Time), and 2) to get this data outside the structure (Delay Time). Communication with the outside is assumed to be performed by a static robot designated as the Command Station. Since it is unlikely that there will be sufficient robots to provide full communications coverage of the area, robots that discover victims are faced with the difficult decision of whether they should continue searching or return with the victim data. We investigate a variety of search techniques and see how the application of biological foraging models can help to streamline the search process, while we have also implemented an opportunistic network to ensure that data are shared whenever robots come within line of sight of each other or the Command Station. We examine this trade-off between performing a search and communicating the results.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130469812","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534890
G. Bianchi, A. Detti, P. Loreti, Claudio Pisa, Srisakul Thakolsri, W. Kellerer, J. Widmer
Thanks to its in-network drop-based adaptation capabilities, H.264 Scalable Video Coding is perceived as an effective approach for delivering video over networks characterized by sudden large bandwidth fluctuations, such as Wireless LANs. Performance may be boosted by the adoption of application-aware/cross-layer schedulers devised to intelligently drop video data units (NALUs), so that i) decoding dependencies are preserved, and ii) the quality perceived by the end users is maximized. In this paper, we provide a theoretical formulation of a QoE utility-optimal cross-layer scheduling problem for H.264 SVC downlink delivery over WLANs. We show that, because of the unique characteristics of the WLAN MAC operation, this problem significantly differs from related approaches proposed for scheduled wireless technologies, especially when the WLAN carries background traffic in the uplink direction. From these theoretical insights, we derive, design, implement and experimentally assess a simple practical scheduling algorithm, whose performance is very close to the optimal solution.
{"title":"Cross-layer H.264 scalable video downstream delivery over WLANs","authors":"G. Bianchi, A. Detti, P. Loreti, Claudio Pisa, Srisakul Thakolsri, W. Kellerer, J. Widmer","doi":"10.1109/WOWMOM.2010.5534890","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534890","url":null,"abstract":"Thanks to its in-network drop-based adaptation capabilities, H.264 Scalable Video Coding is perceived as an effective approach for delivering video over networks characterized by sudden large bandwidth fluctuations, such as Wireless LANs. Performance may be boosted by the adoption of application-aware/cross-layer schedulers devised to intelligently drop video data units (NALUs), so that i) decoding dependencies are preserved, and ii) the quality perceived by the end users is maximized. In this paper, we provide a theoretical formulation of a QoE utility-optimal cross-layer scheduling problem for H.264 SVC downlink delivery over WLANs. We show that, because of the unique characteristics of the WLAN MAC operation, this problem significantly differs from related approaches proposed for scheduled wireless technologies, especially when the WLAN carries background traffic in the uplink direction. From these theoretical insights, we derive, design, implement and experimentally assess a simple practical scheduling algorithm, whose performance is very close to the optimal solution.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123344269","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 : 2010-06-14DOI: 10.1109/WOWMOM.2010.5534892
C. Ververidis, Janne Riihijärvi, P. Mähönen
In this paper we study the problem of quantifying the value of spectrum opportunities to secondary users in Dynamic Spectrum Access (DSA) systems. We especially focus on estimating the impact of key channel parameters, namely the activity patterns of the primary users on the expected quality of experience for secondary users accessing video streams over a DSA system. In our study we consider three basic types of video representing typical video content categorized according to scene change rate ranging from low-activity newscast to high-activity sports video. Through extensive simulations we show that given some information on the expected level of activity in the video, the duty cycle of the primary user alone can yield good predictors for the expected quality of experience of secondary users. Knowledge of the precise distributions of the primary user ON and OFF periods can be used to further enhance the precision of the prediction, but at least for exponential and log-normal channel access patterns the differences are rather small. Finally, we study the problem of determining the channel statistics that are needed to apply the predictor in an optimization setting. Our simulations show that high accuracy can be achieved in matter of minutes of estimation time, which is more than enough for practical deployments in typical urban environments.
{"title":"Evaluation of quality of experience for video streaming over dynamic spectrum access systems","authors":"C. Ververidis, Janne Riihijärvi, P. Mähönen","doi":"10.1109/WOWMOM.2010.5534892","DOIUrl":"https://doi.org/10.1109/WOWMOM.2010.5534892","url":null,"abstract":"In this paper we study the problem of quantifying the value of spectrum opportunities to secondary users in Dynamic Spectrum Access (DSA) systems. We especially focus on estimating the impact of key channel parameters, namely the activity patterns of the primary users on the expected quality of experience for secondary users accessing video streams over a DSA system. In our study we consider three basic types of video representing typical video content categorized according to scene change rate ranging from low-activity newscast to high-activity sports video. Through extensive simulations we show that given some information on the expected level of activity in the video, the duty cycle of the primary user alone can yield good predictors for the expected quality of experience of secondary users. Knowledge of the precise distributions of the primary user ON and OFF periods can be used to further enhance the precision of the prediction, but at least for exponential and log-normal channel access patterns the differences are rather small. Finally, we study the problem of determining the channel statistics that are needed to apply the predictor in an optimization setting. Our simulations show that high accuracy can be achieved in matter of minutes of estimation time, which is more than enough for practical deployments in typical urban environments.","PeriodicalId":384628,"journal":{"name":"2010 IEEE International Symposium on \"A World of Wireless, Mobile and Multimedia Networks\" (WoWMoM)","volume":"462 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123373338","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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