Design of a Configurable Wireless Network Testbed with Live Traffic

Proceedings of the 16th ACM International Conference on Modeling, Analysis &Amp; Simulation of Wireless and Mobile Systems

2013

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A typical wireless network exhibits time-varying channel conditions and complex interference relationships, which are also influenced by different vendor implementations. Therefore, to improve the mapping between wireless simulation and real life, site and device specific models are needed. In this paper, we propose such interference models, called BOWLsim-advanced, based on measurements in two WiFi testbeds. We validate BOWLsim-advanced in complex interference scenarios comprising of hidden terminals, multi-hop flows, and inter-flow interference and show that it has better accuracy compared to both our earlier work and the default interference model of ns-3 (Network Simulator 3). However, the maximum improvement is observed for hidden terminals at the PHY layer, and for multi-hop flows and unicast communication, performance varies based on whether nodes are able to carrier-sense each other or have asymmetric interference. Essentially, our results show that PHY-layer models become insufficient for asymmetric interference, which requires better MAC layer models for higher accuracy.

Section: Introductionmentioning

confidence: 88%

Measurement-based simulation of WiFi interference

Al-Bado

Proceedings of the 16th ACM International Conference on Modeling, Analysis &Amp; Simulation of Wireless and Mobile Systems

2013

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“…Our simulation models are based on measurements carried out in the BOWL indoor testbed [9] at Telekom Innovation Laboratories, in Berlin, Germany. In this section, we first describe our testbed and then, explain our BOWL Indoor Model (BIM), which forms the basis for this work.…”

Section: Bowl Testbed and Indoor Simulation Modelmentioning

confidence: 99%

“…In previous work, we underlined the importance of measurementbased site-specific link models [8] to be able to represent different characteristics of a wireless network. In this paper, our objective is to determine the necessary and sufficient detail for our wireless models to create a realistic representation of our BOWL indoor wireless network testbed [9]. Our overarching goal is to incite the creation of a collection of site-specific models in simulators in the community, which will lead to evaluation of new ideas in simulators in as many diverse conditions as possible.…”

Section: Introductionmentioning

confidence: 99%

What details are needed for wireless simulations? - A study of a site-specific indoor wireless model

Al-Bado

2012 Proceedings IEEE INFOCOM

Merz

2012

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The wireless networking community continuously questions the accuracy and validity of simulation-based performance evaluations. The main reason is the lack of widely-accepted models that represent the real wireless characteristics, especially at the physical (PHY) layer. Hence, the trend in wireless networking is to rely more and more on testbeds, which on one hand bring more realism to network and protocol evaluation, but on the other hand present a high implementation barrier before an idea is ready to be tested. Therefore, realistic network simulators are still very much needed to reduce the time and effort for "concept testing" of novel ideas. In this case, the main question is how detailed should wireless simulators be to evaluate network and protocol performance. In this paper, we attempt a first answer to this question by using the Berlin Open Wireless Lab (BOWL) indoor model (BIM) in the ns-3 simulator. BIM includes several measurement-based models to characterize wireless communication such as frame detection ratio (FDR), frame error ratio (FER), capture and interference models. Through extensive measurements, we analyze the accuracy that we obtain with these PHY-layer models. Our experiments also show whether the detailed models at the PHY layer play an important role to represent transport layer performance in simulations.

“…All the measurements were performed on the BOWL network [19], an outdoor wireless mesh network deployed on the rooftop of the TU Berlin campus. The network comprises two separate networks, a 50-node network equipped with Avila Gateworks GW2348-4 motherboard, and a 13-node network with Asus WL-500GP Routers.…”

Section: A Network and Node Setupmentioning

confidence: 99%

Joint Transmission Rate, Power, and Carrier Sense Settings: An Initial Measurement Study

Huehn

Merz

2010 Fifth IEEE Workshop on Wireless Mesh Networks

2010

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Abstract-A substantial variety of control algorithms to adjust carrier sensing, transmission power, and transmission rate have been proposed for IEEE 802.11 wireless networks in the recent literature. Their objectives range from maximizing throughput, spatial reuse, and fairness to minimizing interference and congestion within the network. However, only a few of these have been implemented and analysed in practice, often because accessing and changing the necessary parameters in the wireless hardware is too difficult. Essentially, there is little understanding about the interactions of jointly adjusted transmission rate, power and carrier sense thresholds, and their impact on the aforementioned objectives. Therefore, in this paper, we focus on transmission rate, power and carrier sensing settings. We provide a detailed description of the common IEEE 802.11 radio hardware, especially in terms of carrier-sensing circuitry. We then present our results from our validation and initial measurement study, which demonstrate interactions between transmit power and rate under different carrier-sensing settings in a two link scenario. Our initial findings indicate there exists a limited number of ratepower combinations that achieve high performance in terms of either throughput and fairness both with and without carrier sensing. Furthermore, in the case of both strong and weak links exist in the network, turning carrier sensing off significantly improves performance.