Search results for "Hidden node problem"

showing 6 items of 6 documents

Joint Usage of Dynamic Sensitivity Control and Time Division Multiple Access in Dense 802.11ax Networks

2016

It is well known that in case of high density deployments, Wi-Fi networks suffer from serious performance impairments due to hid- den and exposed nodes. The problem is explicitly considered by the IEEE 802.11ax developers in order to improve spectrum efficiency. In this pa- per, we propose and evaluate the joint usage of dynamic sensitivity con- trol (DSC) and time division multiple access (TDMA) for improving the spectrum allocation among overlapping 802.11ax BSSs. To validate the solution, apart from simulation, we used a testbed based on the Wireless MAC Processor (WMP), a prototype of a programmable wireless card.

Computer scienceReal-time computingTime division multiple access050801 communication & media studies02 engineering and technologyFrequency allocation0508 media and communications0202 electrical engineering electronic engineering information engineeringWirelessDense deploymentIEEE 802.11axHidden node problembusiness.industryExposed node problemSettore ING-INF/03 - TelecomunicazioniDynamic sensitivity control05 social sciencesTestbedSpectral efficiencyExposed node problemIEEE 802.11axTDMA020201 artificial intelligence & image processingHidden node problembusinessComputer network
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Adaptive Collision Avoidance through Implicit Acknowledgments in WSNs

2008

The large number of nodes, typical of many sensor network deployments, and the well-known hidden terminal problem make collision avoidance an essential goal for the actual employment of WSN technology. Collision avoidance is traditionally dealt with at the MAC Layer and plenty of different solutions have been proposed, which however have encountered limited diffusion because of their incompatibility with commonly available devices.In this paper we propose an approach to collision avoidance which is designed to work over a standard MAC Layer, namely the IEEE 802.15.4 MAC, and is based on application-controlled delays of packet transmission times. The proposed scheme is simple, decentralized …

Hidden node problemComputer sciencebusiness.industryComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKSSynchronizationTree (data structure)ScalabilityMultiple Access with Collision Avoidance for WirelessWireless Sensor NetworksbusinessWireless sensor networkCollision avoidanceCarrier sense multiple access with collision avoidanceComputer network2008 IEEE Asia-Pacific Services Computing Conference
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Cooperative RTS/CTS MAC with relay selection in distributed wireless networks

2009

This paper proposes a cooperative multiple access protocol based on the Distributed Coordination Function (DCF) Request-To-Send/Clear-To-Send (RTS/CTS) scheme for distributed wireless networks. It answers three key questions concerning cooperation from the network perspective, namely when to cooperate, whom to cooperate with and how to protect cooperative transmissions. According to our protocol, the cooperation is initiated only if the direct transmission fails. An optimal relay node is selected in a distributed manner according to instantaneous relay channel conditions without prior information or extra signaling among relay candidates in the network. An additional three-way handshake is …

Hidden node problemComputer sciencebusiness.industryWireless networkNode (networking)ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKSDistributed coordination functionlaw.inventionCooperative diversityRelaylawMultiple Access with Collision Avoidance for WirelessbusinessRelay channelComputer network2009 International Conference on Ultra Modern Telecommunications & Workshops
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Revisit of RTS/CTS Exchange in High-Speed IEEE 802.11 Networks

2005

IEEE 802.11 medium access control (MAC), called distributed coordination function (DCF), provides two different access modes, namely, 2-way (basic access) and 4-way (RTS/CTS) handshaking. The 4-way handshaking has been introduced in order to combat the hidden terminal phenomenon. It has been also proved that such a mechanism can be beneficial even in the absence of hidden terminals, because of the collision time reduction. We analyze the effectiveness of the RTS/CTS access mode, in current 802.11b and 802.11a networks. Since the rates employed for control frame transmissions can be much lower than the rate employed for data frames, the assumption on the basis of the 4-way handshaking introd…

Hidden node problembusiness.industryComputer scienceReal-time computingFrame (networking)Wireless local area networks (WLAN)Distributed coordination functionThroughputbackoff algorithmHandshakingMedia access controlMultiple Access with Collision Avoidance for WirelessIEEE 802.11e-2005businessCarrier sense multiple access with collision avoidanceComputer networkSixth IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks
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Supporting a Pseudo-TDMA Access Scheme in Mesh Wireless Networks

2013

Wireless mesh networks appear a promising solution for pro- viding ubiquitous low-cost wireless access, but cannot rely on simple CSMA access protocols because of the critical inefficiencies that arise in topologies with hidden nodes. To overcome these limitations, some important protocol extensions based on synchronization and reservation mechanisms have been ratified. In this paper we show that an alternative approach to the standardiza- tion of new features and signaling messages for mesh networks can be the utilization of programmable nodes able to execute different MAC protocols programmed on the fly. Signaling messages are used only for disseminating the new protocol among the nodes. …

Wireless mesh networkHidden node problembusiness.industryComputer scienceWireless networkSettore ING-INF/03 - TelecomunicazioniDistributed computingComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKSOrder One Network ProtocolShared meshKey distribution in wireless sensor networkswireless mesh networks synchronization pseudo-TDMA random accessbusinessComputer networkIEEE 802.11sWireless distribution system
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Moving RTS/CTS to the frequency domain: an efficient contention scheme for 802.11ax networks

2019

In this paper, we propose a contention mechanism based on the execution of multiple contention rounds in the frequency domain (ReCHo), which is designed to offer high throughput performance and robustness with respect to imperfect carrier sensing. The main idea is using narrow tones as signalling messages for performing channel access contentions and allowing the Access Point (AP) to echo these signals, in order to extend the sensing capabilities to all the stations associated to the AP. In particular, we refer to the emerging IEEE 802.11ax standard, showing how our scheme can boost performance of random access with respect to the current version of IEEE 802.11ax OFDMA Back-Off (OBO), even …

imperfect sensingHidden node problemSettore ING-INF/03 - TelecomunicazioniOrthogonal frequency-division multiplexingComputer sciencebusiness.industryMechanism based020206 networking & telecommunications02 engineering and technologySignallingFrequency-domain signallingRobustness (computer science)020204 information systemsFrequency domainTelecommunications link0202 electrical engineering electronic engineering information engineeringfrequency-domain signalling; IEEE 802.11ax; imperfect sensing; random access contentionrandom access contentionbusinessIEEE 802.11axRandom accessComputer network
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