In a large scale Bluetooth network, scatternet has been regarded as the only interconnection method among piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. Overlaid Bluetooth Piconets (OBP) interconnects piconets and forms a virtual scatternet. This demo shows the possibility of using OBP instead of Scatternet for Video Streaming.
{"title":"Video streaming over overlaid bluetooth piconets (OBP)","authors":"Sewook Jung, A. Chang, M. Gerla","doi":"10.1145/1160987.1161021","DOIUrl":"https://doi.org/10.1145/1160987.1161021","url":null,"abstract":"In a large scale Bluetooth network, scatternet has been regarded as the only interconnection method among piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. Overlaid Bluetooth Piconets (OBP) interconnects piconets and forms a virtual scatternet. This demo shows the possibility of using OBP instead of Scatternet for Video Streaming.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121104273","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}
B. Raman, Kameswari Chebrolu, N. Madabhushi, Dattatraya Y. Gokhale, Phani Kumar Valiveti, Dheeraj Jain
In this work, we consider sensor networks used for scientific instrumentation, where we have a set of nodes collecting data and relaying the same to a central base node. From the point of view of deploying such networks,we re-look at the design choices available for the network architecture and protocol design. A design choice which has not received in-depth attention thus far is the use of external antennas for improving the communication range. We present extensive measurements to quantify the use of external antennas. We show that this is a simple yet effective mechanism, in many cases allowing the use of just a single-hop network architecture. Such an approach of course, also greatly simplifies protocol design. Related to the range studies, we also look at the time variability of RSSI and the packet error rate. We find variability at time scales as small as a single packet and also at several hours. Given this, we argue that dynamic metric based routing becomes highly questionable, and a centralized protocol design becomes a serious alternative.
{"title":"Implications of link range and (In)stability on sensor network architecture","authors":"B. Raman, Kameswari Chebrolu, N. Madabhushi, Dattatraya Y. Gokhale, Phani Kumar Valiveti, Dheeraj Jain","doi":"10.1145/1160987.1161000","DOIUrl":"https://doi.org/10.1145/1160987.1161000","url":null,"abstract":"In this work, we consider sensor networks used for scientific instrumentation, where we have a set of nodes collecting data and relaying the same to a central base node. From the point of view of deploying such networks,we re-look at the design choices available for the network architecture and protocol design. A design choice which has not received in-depth attention thus far is the use of external antennas for improving the communication range. We present extensive measurements to quantify the use of external antennas. We show that this is a simple yet effective mechanism, in many cases allowing the use of just a single-hop network architecture. Such an approach of course, also greatly simplifies protocol design. Related to the range studies, we also look at the time variability of RSSI and the packet error rate. We find variability at time scales as small as a single packet and also at several hours. Given this, we argue that dynamic metric based routing becomes highly questionable, and a centralized protocol design becomes a serious alternative.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134589906","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-speed wireless backbones have the potential to replace or complement wired connections. This paper provides a comprehensive network and transport layer performance evaluation of the Magnets WiFi backbone. The backbone, deployed in a metropolitan area of Berlin, consists of six 108 Mbps capable links using directional antennas and spans over 2.3 km. Built with off-the-shelf hardware, it features mixed 802.11a/g technology, link distances between 330 m and 930 m and support for two enhanced MAC/PHY layer modes at the access points (AP) to improve their performance. These unique characteristics provide a challenging environment to investigate the impact of a wide range of parameters. In particular, using CBR and VBR traffic profiles, we assess the influence of distance, 802.11 technology and AP modes on throughput, delay, packet loss and jitter between pairs of adjacent nodes. For example, our measurements show that the average UDP throughput of the 802.11g links varies between 15.9 and 18.7 Mbps, whereas the 802.11a link achieves 27.8 Mbps. Finally, the average UDP throughput can even be increased to 55.2 Mbps by concomitantly enabling the two enhanced AP modes.
{"title":"Experimental evaluation and characterization of the magnets wireless backbone","authors":"R. Karrer, I. Matyasovszki, A. Botta, A. Pescapé","doi":"10.1145/1160987.1160994","DOIUrl":"https://doi.org/10.1145/1160987.1160994","url":null,"abstract":"High-speed wireless backbones have the potential to replace or complement wired connections. This paper provides a comprehensive network and transport layer performance evaluation of the Magnets WiFi backbone. The backbone, deployed in a metropolitan area of Berlin, consists of six 108 Mbps capable links using directional antennas and spans over 2.3 km. Built with off-the-shelf hardware, it features mixed 802.11a/g technology, link distances between 330 m and 930 m and support for two enhanced MAC/PHY layer modes at the access points (AP) to improve their performance. These unique characteristics provide a challenging environment to investigate the impact of a wide range of parameters. In particular, using CBR and VBR traffic profiles, we assess the influence of distance, 802.11 technology and AP modes on throughput, delay, packet loss and jitter between pairs of adjacent nodes. For example, our measurements show that the average UDP throughput of the 802.11g links varies between 15.9 and 18.7 Mbps, whereas the 802.11a link achieves 27.8 Mbps. Finally, the average UDP throughput can even be increased to 55.2 Mbps by concomitantly enabling the two enhanced AP modes.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"172 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116603570","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 extended abstract describes our experiences in the deployment of QuRiNet, a wireless mesh network at the Quail Ridge Natural Reserve. Quail Ridge boasts 2,000 acres of untouched wilderness on a peninsula of Lake Berryessa, California. In deploying a mesh network at Quail Ridge, we seek to assist ecological research in the area by providing a communications infrastructure and also provide a platform for wireless mesh networks research. The network currently comprises of about six nodes and supports three video cameras and a few audio sensors. We plan to deploy five more nodes in the near future, with about twenty nodes being the final goal. This abstract will describe our work in deploying this network and give the reader an overview of our current system and deployment status.
{"title":"QuRiNet: quail ridge natural reserve wireless mesh network","authors":"Daniel Wu, Dhruv Gupta, S. Liese, P. Mohapatra","doi":"10.1145/1160987.1161015","DOIUrl":"https://doi.org/10.1145/1160987.1161015","url":null,"abstract":"This extended abstract describes our experiences in the deployment of QuRiNet, a wireless mesh network at the Quail Ridge Natural Reserve. Quail Ridge boasts 2,000 acres of untouched wilderness on a peninsula of Lake Berryessa, California. In deploying a mesh network at Quail Ridge, we seek to assist ecological research in the area by providing a communications infrastructure and also provide a platform for wireless mesh networks research. The network currently comprises of about six nodes and supports three video cameras and a few audio sensors. We plan to deploy five more nodes in the near future, with about twenty nodes being the final goal. This abstract will describe our work in deploying this network and give the reader an overview of our current system and deployment status.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127797604","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. Zimmermann, M. Günes, Martin Wenig, J. Ritzerfeld, Ulrich Meis
The study of wireless and mobile networks is mainly based on simulations. Although simulation environments offer a convenient combination of flexibility and controllability, their largest disadvantage is that the results gained by using them are difficult to transfer into reality. This is due to the complex environment of mobile and wireless networks.In this paper we introduce a hybrid testbed approach, which consists of real mesh nodes and a virtualization environment. This combination provides on the one hand a flexible development environment for distributed network protocols and applications, and on the other hand a high degree in realism. Therefore, it allows the design and conduction of large scale networks where the results are easily transferred to the real world.
{"title":"Architecture of the hybrid MCG-mesh testbed","authors":"A. Zimmermann, M. Günes, Martin Wenig, J. Ritzerfeld, Ulrich Meis","doi":"10.1145/1160987.1161004","DOIUrl":"https://doi.org/10.1145/1160987.1161004","url":null,"abstract":"The study of wireless and mobile networks is mainly based on simulations. Although simulation environments offer a convenient combination of flexibility and controllability, their largest disadvantage is that the results gained by using them are difficult to transfer into reality. This is due to the complex environment of mobile and wireless networks.In this paper we introduce a hybrid testbed approach, which consists of real mesh nodes and a virtualization environment. This combination provides on the one hand a flexible development environment for distributed network protocols and applications, and on the other hand a high degree in realism. Therefore, it allows the design and conduction of large scale networks where the results are easily transferred to the real world.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134422452","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 the past decade, wireless multihop networks have caught the fancy of wireless networking researchers and practitioners alike. However, wireless being a broadcast medium, links in close neighborhood interfere causing a capacity degradation. Network modeling community has investigated this issue of interference and how it limits the capacity of wireless multihop networks [3]. Much of these works use a somewhat abstract and idealized model of interference, initially proposed in the seminal work of Gupta and Kumar [2]. These models describe how two communicating links interfere based on physical distances between the transmitters and receivers, oversimplified radio propagation model, idealized transmitter and receiver characteristics, and so on. Such models have so far been sufficient for getting a highlevel understanding of the behavior of wireless networks and even for designing protocol support, but it has remained unclear how these models could be useful in practice for an operational network. Research in Wireless Networks needs to consider the phenomenon of interference between transmissions. A model for interference is an essential input to the design of any routing protocol. Design of a fairness model, or a capacity model for a wireless network also requires an interference model. Transport protocols and channel assignment protocols also need an understanding of wireless interference. So, its imperative to have a realistic and accurate interference model to assist research in various areas in wireless networking. Our work follows on the lines of previous works done on developing a measurement based model for quantifying the interference limited link capacity [4, 5]. In this work, we estimate the impact of interference on the transmission capacity of a node. When a node transmits a packet, all the other nodes who can either receive the packet, or can detect the transmission’s signal become silent. Thus, a transmitter
{"title":"A measurement-based model for estimating transmission capacity in a wireless mesh network","authors":"A. Kashyap, S. Ganguly, Samir R Das","doi":"10.1145/1160987.1161012","DOIUrl":"https://doi.org/10.1145/1160987.1161012","url":null,"abstract":"In the past decade, wireless multihop networks have caught the fancy of wireless networking researchers and practitioners alike. However, wireless being a broadcast medium, links in close neighborhood interfere causing a capacity degradation. Network modeling community has investigated this issue of interference and how it limits the capacity of wireless multihop networks [3]. Much of these works use a somewhat abstract and idealized model of interference, initially proposed in the seminal work of Gupta and Kumar [2]. These models describe how two communicating links interfere based on physical distances between the transmitters and receivers, oversimplified radio propagation model, idealized transmitter and receiver characteristics, and so on. Such models have so far been sufficient for getting a highlevel understanding of the behavior of wireless networks and even for designing protocol support, but it has remained unclear how these models could be useful in practice for an operational network. Research in Wireless Networks needs to consider the phenomenon of interference between transmissions. A model for interference is an essential input to the design of any routing protocol. Design of a fairness model, or a capacity model for a wireless network also requires an interference model. Transport protocols and channel assignment protocols also need an understanding of wireless interference. So, its imperative to have a realistic and accurate interference model to assist research in various areas in wireless networking. Our work follows on the lines of previous works done on developing a measurement based model for quantifying the interference limited link capacity [4, 5]. In this work, we estimate the impact of interference on the transmission capacity of a node. When a node transmits a packet, all the other nodes who can either receive the packet, or can detect the transmission’s signal become silent. Thus, a transmitter","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114547486","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}
Saumitra M. Das, Dimitrios Koutsonikolas, Y. C. Hu, D. Peroulis
Wireless mesh networks (WMNs) have been proposed as a solution for ubiquitous last-mile broadband access. A critical limiting factor for many WMN protocols in realizing their throughput potential is the interference between nodes in the WMN. Understanding and characterizing such interference is important for a variety of purposes such as channel assignment, route selection, and fair scheduling. Instead of using ad hoc heuristics, a recent study proposed characterizing interference in a WMN by measuring two-way interference, i.e., interference between each pair of communicating links.In this paper, we study the extent of multi-way interference, i.e., the interference caused by multiple transmitters to a communicating link. We find through simulations and through measurements of a 32-node wireless testbed that even if these transmitters individually do not interfere significantly with a given communicating link, simultaneous transmissions of them have the potential to significantly affect the throughput of the communicating link. This implies that pairwise interference measurements may be optimistic when used to drive protocols in wireless mesh networks. Encouragingly, we find that this phenomenon, although significant when it occurs, is not widespread. In particular, multi-way interference caused significant additional throughput degradation compared to pairwise interference to a small fraction of the links in the testbed over our measurement period. In addition, we find that there is a strong correlation between the impact of multi-way interference and the quality of the link under consideration. We conclude with recommendations on how protocols should take multi-way interference into account.
{"title":"Characterizing multi-way interference in wireless mesh networks","authors":"Saumitra M. Das, Dimitrios Koutsonikolas, Y. C. Hu, D. Peroulis","doi":"10.1145/1160987.1160999","DOIUrl":"https://doi.org/10.1145/1160987.1160999","url":null,"abstract":"Wireless mesh networks (WMNs) have been proposed as a solution for ubiquitous last-mile broadband access. A critical limiting factor for many WMN protocols in realizing their throughput potential is the interference between nodes in the WMN. Understanding and characterizing such interference is important for a variety of purposes such as channel assignment, route selection, and fair scheduling. Instead of using ad hoc heuristics, a recent study proposed characterizing interference in a WMN by measuring two-way interference, i.e., interference between each pair of communicating links.In this paper, we study the extent of multi-way interference, i.e., the interference caused by multiple transmitters to a communicating link. We find through simulations and through measurements of a 32-node wireless testbed that even if these transmitters individually do not interfere significantly with a given communicating link, simultaneous transmissions of them have the potential to significantly affect the throughput of the communicating link. This implies that pairwise interference measurements may be optimistic when used to drive protocols in wireless mesh networks. Encouragingly, we find that this phenomenon, although significant when it occurs, is not widespread. In particular, multi-way interference caused significant additional throughput degradation compared to pairwise interference to a small fraction of the links in the testbed over our measurement period. In addition, we find that there is a strong correlation between the impact of multi-way interference and the quality of the link under consideration. We conclude with recommendations on how protocols should take multi-way interference into account.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115742876","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}
The application of a reliable communication infrastructure in emergency situations is the focus of this project. Communication and interoperability between different organizations of first responders has been a problem for a long time. There have been examples of failure in communication between different organizations at World Trade Center on 9/11: for example some of the police warnings were not heard by fire fighters that resulted in several lives lost. In most cases, network unavailability or incapability of coordination among networks causes much damage. A communication infrastructure has specific requirements to be widely deployable at emergency applications such as high reliability, robustness, interoperability with existing technologies, quick reconfiguration, and low cost. It must be able to operate in a highly distributed and infrastructure-less manner, quickly deployable, easy to reconfigure, and allocate network resources efficiently. We propose a Hybrid Wireless Mesh Network as a well-suited candidate capable of creating a communication infrastructure where the existing communication infrastructure is damaged or unavailable. This infrastructure has the ability to work in a heterogeneous environment where different technologies might be available as backhaul through multiple interface cards designed in Calit2's CalMesh boxes. In addition to the technical constraints in such a demanding environment, we must consider some of the sociological problems that arise when new technologies are introduced, including resistance to technology adoption, and designing new warning systems to utilize the new infrastructure, and concerns surrounding sharing information and privacy.In our research to date, we have deployed a HWMN made up of Calit2's interoperable CalMesh nodes at a full-scale crisis response drill organized by the San Diego Metropolitan Medical Strike Team (MMST) in which we were able to collect network statistical data from the medical first responders' communication over the network we deployed.We are also developing our simulation results in cellular networks investigating different real scenarios that may occur at ground zero. We would like to extract mobility patterns and channel characterization from real world scenarios to integrate this simulation results with other transportation and evacuation simulators in order to allocate network resources more efficiently, and route traffic effectively to insure that cellular infrastructures are not overloaded so that broadcast warnings and messages are still received by evacuees.
{"title":"Hybrid wireless mesh network deployment: a communication testbed for disaster scenarios","authors":"R. Dilmaghani, R. Rao","doi":"10.1145/1160987.1161005","DOIUrl":"https://doi.org/10.1145/1160987.1161005","url":null,"abstract":"The application of a reliable communication infrastructure in emergency situations is the focus of this project. Communication and interoperability between different organizations of first responders has been a problem for a long time. There have been examples of failure in communication between different organizations at World Trade Center on 9/11: for example some of the police warnings were not heard by fire fighters that resulted in several lives lost. In most cases, network unavailability or incapability of coordination among networks causes much damage. A communication infrastructure has specific requirements to be widely deployable at emergency applications such as high reliability, robustness, interoperability with existing technologies, quick reconfiguration, and low cost. It must be able to operate in a highly distributed and infrastructure-less manner, quickly deployable, easy to reconfigure, and allocate network resources efficiently. We propose a Hybrid Wireless Mesh Network as a well-suited candidate capable of creating a communication infrastructure where the existing communication infrastructure is damaged or unavailable. This infrastructure has the ability to work in a heterogeneous environment where different technologies might be available as backhaul through multiple interface cards designed in Calit2's CalMesh boxes. In addition to the technical constraints in such a demanding environment, we must consider some of the sociological problems that arise when new technologies are introduced, including resistance to technology adoption, and designing new warning systems to utilize the new infrastructure, and concerns surrounding sharing information and privacy.In our research to date, we have deployed a HWMN made up of Calit2's interoperable CalMesh nodes at a full-scale crisis response drill organized by the San Diego Metropolitan Medical Strike Team (MMST) in which we were able to collect network statistical data from the medical first responders' communication over the network we deployed.We are also developing our simulation results in cellular networks investigating different real scenarios that may occur at ground zero. We would like to extract mobility patterns and channel characterization from real world scenarios to integrate this simulation results with other transportation and evacuation simulators in order to allocate network resources more efficiently, and route traffic effectively to insure that cellular infrastructures are not overloaded so that broadcast warnings and messages are still received by evacuees.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129772592","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}
Indoor ranging and location in WLAN is possible through obtaining Round-Trip-Time (RTT) measurements at data link level. This procedure allows using the existing IEEE 802.11 WLAN infrastructure with minor changes in order to provide an accurate estimation of the position of the mobile terminal. In this paper, an approach to overcome the undesired impact of the indoor radio-channel multipath on the accuracy of the TOA estimation between the terminal and an Access Point is presented. Ranging errors caused by multipath are quantified for different channel profiles: Dominant Direct Path (DDP), Non Dominant Direct Path (NDDP) and Undetectable Direct Path (UDP). However, the main challenge corresponds to be able to identify this profile (i.e. the multipath condition) from the obtained RTT measurements at IEEE 802.11 link level. This allows applying a TOA estimation algorithm sensitive to the detected profile in order to minimize the TOA estimation error.
{"title":"Multipath profile discrimination in TOA-based WLAN ranging with link layer frames","authors":"M. Ciurana, F. Barceló, S. Cugno","doi":"10.1145/1160987.1161001","DOIUrl":"https://doi.org/10.1145/1160987.1161001","url":null,"abstract":"Indoor ranging and location in WLAN is possible through obtaining Round-Trip-Time (RTT) measurements at data link level. This procedure allows using the existing IEEE 802.11 WLAN infrastructure with minor changes in order to provide an accurate estimation of the position of the mobile terminal. In this paper, an approach to overcome the undesired impact of the indoor radio-channel multipath on the accuracy of the TOA estimation between the terminal and an Access Point is presented. Ranging errors caused by multipath are quantified for different channel profiles: Dominant Direct Path (DDP), Non Dominant Direct Path (NDDP) and Undetectable Direct Path (UDP). However, the main challenge corresponds to be able to identify this profile (i.e. the multipath condition) from the obtained RTT measurements at IEEE 802.11 link level. This allows applying a TOA estimation algorithm sensitive to the detected profile in order to minimize the TOA estimation error.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127382095","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}
K. N. Gopinath, P. Bhagwat, Airtight Networks, India K Gopinath
Wireless LAN (WLAN) market consists of IEEE 802.11 MAC standard conformant devices (e.g., access points (APs), client adapters) from multiple vendors. Certain third party certifications such as those specified by the Wi-Fi alliance have been widely used by vendors to ensure basic conformance to the 802.11 standard, thus leading to the expectation that the available devices exhibit identical MAC level behavior. In this paper, however, we present what we believe to be the first ever set of experimental results that highlight the fact that WLAN devices from different vendors in the market can have heterogeneous MAC level behavior. Specifically, we demonstrate with examples and data that in certain cases, devices may not be conformant with the 802.11 standard while in other cases, they may differ in significant details that are not a part of mandatory specifications of the standard. We argue that heterogeneous MAC implementations can adversely impact WLAN operations leading to unfair bandwidth allocation, potential break-down of related MAC functionality and difficulties in provisioning the capacity of a WLAN. However, on the positive side, MAC level heterogeneity can be useful in applications such as vendor/model level device fingerprinting.
{"title":"An empirical analysis of heterogeneity in IEEE 802.11 MAC protocol implementations and its implications","authors":"K. N. Gopinath, P. Bhagwat, Airtight Networks, India K Gopinath","doi":"10.1145/1160987.1161002","DOIUrl":"https://doi.org/10.1145/1160987.1161002","url":null,"abstract":"Wireless LAN (WLAN) market consists of IEEE 802.11 MAC standard conformant devices (e.g., access points (APs), client adapters) from multiple vendors. Certain third party certifications such as those specified by the Wi-Fi alliance have been widely used by vendors to ensure basic conformance to the 802.11 standard, thus leading to the expectation that the available devices exhibit identical MAC level behavior. In this paper, however, we present what we believe to be the first ever set of experimental results that highlight the fact that WLAN devices from different vendors in the market can have heterogeneous MAC level behavior. Specifically, we demonstrate with examples and data that in certain cases, devices may not be conformant with the 802.11 standard while in other cases, they may differ in significant details that are not a part of mandatory specifications of the standard. We argue that heterogeneous MAC implementations can adversely impact WLAN operations leading to unfair bandwidth allocation, potential break-down of related MAC functionality and difficulties in provisioning the capacity of a WLAN. However, on the positive side, MAC level heterogeneity can be useful in applications such as vendor/model level device fingerprinting.","PeriodicalId":439944,"journal":{"name":"Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122205141","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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