6533b837fe1ef96bd12a1ef1
RESEARCH PRODUCT
On the Fidelity of IEEE 802.11 commercial cards
V. AmmirataG. TerrazzinoA. Di StefanoLuca ScaliaA. ScaglioneIlenia TinnirelloGiuseppe BianchiC. Giaconiasubject
Signal processingCommunication channels (information theory); Internet; Signal processing; Wireless telecommunication systems; Baseband signals; Carrier sense function; MAC layer; Network protocolsComputer scienceMAC layerWireless local area networks (WLAN)backoff algorithmCommunication channels (information theory)IEEE 802.11Wireless telecommunication systemsNetwork protocolsThroughput (business)InternetBaseband signalsChannel allocation schemesSIMPLE (military communications protocol)Settore ING-INF/03 - Telecomunicazionibusiness.industryComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKSPhysical layerCarrier sense functionThroughputNetwork interface controllerEmbedded systemResource allocationbusinessComputer networkCommunication channeldescription
The IEEE 802.11 D CF protocol is known to be fair in terms of long-term resource repartition among the contending stations. However, when considering real scenarios, where commercial 802.11 cards interact, very unpredictable as well as sometimes surprising behaviors emerge. Motivation of this paper is to investigate the reasons of the very evident disagreement between the theoretical IEEE 802.11 DCF protocol models and its practical implementations. Inparticular, we try to characterize the card behavior not only in terms of perceived throughput, but also in terms of low-level channel access operations. In fact, the simple throughput analysis does not allow to identify what affecting parameters, both in terms of transceivers architectures and MAC layer deployments, determine the performance differentiation among the cards. To this purpose, we implemented a tunable DCF network card, in which all MAC parameters are programmable and all the baseband signals are available, and we used this card as a probe instrument. We registered the low-level access operations of commercial cards in terms of access times revelead by the carrier sense function of our probe card. By comparing these times, we surprisingly proved that the most evident performance differences are not due to PHY layer issues, but to the MAC implementations, which often seem to do not respect the standard specifications.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2006-10-11 |