| 1. |
- Al Nahas, Beshr, 1985, et al.
(författare)
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Network-wide Consensus Utilizing the Capture Effect in Low-power Wireless Networks
- 2017
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Ingår i: Proceedings of the Conference on Embedded Networked Sensor Systems (ACM SenSys). - New York, NY, USA : ACM. - 9781450354592
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Konferensbidrag (refereegranskat)abstract
- In low-power wireless networking, new applications such as cooperative robots or industrial closed-loop control demand for network-wide agreement at low-latency and high reliability. Distributed consensus protocols is a mature field of research in a wired context, but has received little attention in low-power wireless settings. In this paper, we present A2: Agreement in the Air, a system that brings distributed consensus to low-power multi-hop networks. We introduce Synchrotron, a synchronous transmissions kernel that builds a robust mesh by exploiting the capture effect, frequency hopping with parallel channels, and link-layer security. We build A2 on top of this reliable base layer, and enable the two- and three-phase commit protocols, as well as network services such as joining, hopping sequence distribution and re-keying.We evaluate A2 on four public testbeds with different deployment densities and sizes. A2 requires only 475 ms to complete a two-phase commit over 180 nodes. The resulting duty cycle is 0.5 percent for 1-minute intervals. We show that A2 achieves zero losses end-to-end over long experiments, representing millions of data points.When further adding controlled failures, we show that two-phase commit ensures transaction consistency in A2 while three-phase commit provides liveness at the expense of inconsistency under specific failure scenarios.
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| 2. |
- Al Nahas, Beshr, 1985, et al.
(författare)
-
Poster abstract : Network bootstrapping and leader election utilizing the capture effect in low-power wireless networks
- 2017
-
Ingår i: SenSys 2017 - Proceedings of the 15th ACM Conference on Embedded Networked Sensor Systems. - New York, NY, USA : Association for Computing Machinery, Inc. - 9781450354592
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Konferensbidrag (refereegranskat)abstract
- Many protocols in low-power wireless networks require a leader to bootstrap and maintain their operation. For example, Chaos and Glossy networks need an initiator to synchronize and initiate the communication rounds. Commonly, these protocols use a fixed, compile-time defined node as the leader. In this work, we tackle the challenge of dynamically bootstrapping the network and electing a leader in low-power wireless scenarios.
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| 3. |
- Iqbal, Hassan, et al.
(författare)
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Poster Abstract: Taming Link-layer Heterogeneity in IoT through Interleaving Multiple Link-Layers over a Single Radio
- 2017
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Ingår i: SenSys 2017 - Proceedings of the 15th ACM Conference on Embedded Networked Sensor Systems. - New York, NY, USA : ACM. - 9781450354592 ; 2017-January
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Konferensbidrag (refereegranskat)abstract
- We propose dynamic reconfiguration of the radio interface in IoT platforms to support multiple link layers simultaneously. This allows us to tackle the increasing link layer heterogeneity in IoT devices, thus bringing a multitude of benefits: extensible and vender agnostic multihop deployments, rapid integration of the new “things” into an existing network, as well as seamless integration of the IoT with the traditional wireless Internet.
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| 4. |
- Pérez-Penichet, Carlos, et al.
(författare)
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Poster abstract : Augmenting WSNs with interoperable 802.15.4 sensor tags
- 2017
-
Ingår i: SenSys 2017 - Proceedings of the 15th ACM Conference on Embedded Networked Sensor Systems. - New York, NY, USA : Association for Computing Machinery, Inc. - 9781450354592
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Konferensbidrag (refereegranskat)abstract
- The sensing capabilities of most sensor networks are fixed at the time of deployment. Adding new sensing capabilities to such networks is a costly and cumbersome process. We present Passive Sensor Tags, battery-free sensing devices that could be used to extend the sensing capabilities of an existing network. Sensor tags feature our new 802.15.4 receiver design which is suitable for micro-power operation, making battery-free tags possible. Because our tags can both transmit and receive 802.15.4 frames there is no need for any modification to the deployed hardware. We present preliminary measurements of transmission and reception range.
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| 5. |
- Varshney, Ambuj, et al.
(författare)
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Demo: LoRea : A backscatter architecture that achieves a long communication range
- 2017
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Ingår i: Proc. 15th ACM Conference on Embedded Network Sensor Systems. - New York : ACM Press. - 9781450354592
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Konferensbidrag (refereegranskat)abstract
- We present LoRea an architecture consisting of a backscatter tag, a reader and multiple carrier generators that overcomes the power, cost and range limitations of existing backscatter systems such as Computational Radio Frequency Identification (CRFID). LoRea achieves this by: First, generating narrow-band backscatter transmissions. Second, by mitigating self-interference without the complex designs employed on RFID readers by keeping carrier signal and backscattered signal apart in frequency. Finally, by decoupling carrier generation from the reader and using devices such as WiFi routers and sensor nodes as a source of the carrier signal. LoRea's communication range scales with the carrier strength, and proximity to the carrier source and achieves a maximum range of 3.4 km when the tag is located 1 m from the carrier source while consuming 70 mu Ws at the backscatter tag. We present various ultra-low power and long-range features of the LoRea architecture.
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| 6. |
- Varshney, Ambuj, et al.
(författare)
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LoRea: A Backscatter Architecture that Achieves a Long Communication Range
- 2017
-
Ingår i: Proc. 15th ACM Conference on Embedded Network Sensor Systems. - New York, NY, USA : ACM. - 9781450354592
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Konferensbidrag (refereegranskat)abstract
- There is the long-standing assumption that radio communication inthe range of hundreds of meters needs to consume mWs of powerat the transmitting device. In this paper, we demonstrate that this isnot necessarily the case for some devices equipped with backscatterradios. We present LoRea an architecture consisting of a tag, areader and multiple carrier generators that overcomes the power,cost and range limitations of existing systems such as ComputationalRadio Frequency Identication (CRFID). LoRea achieves thisby: First, generating narrow-band backscatter transmissions thatimprove receiver sensitivity. Second, mitigating self-interferencewithout the complex designs employed on RFID readers by keepingcarrier signal and backscattered signal apart in frequency. Finally,decoupling carrier generation from the reader and using devicessuch as WiFi routers and sensor nodes as a source of the carriersignal. An o-the-shelf implementation of LoRea costs 70 USD,a drastic reduction in price considering commercial RFID readerscost 2000 USD. LoRea’s range scales with the carrier strength, andproximity to the carrier source and achieves a maximum range of3:4 km when the tag is located at 1m distance from a 28 dBm carriersource while consuming 70 µW at the tag. When the tag is equidistantfrom the carrier source and the receiver, we can communicateupto 75m, a signicant improvement over existing RFID readers.
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