Bandwidth Estimation for IEEE Bandwidth Estimation for IEEE 802.11-Based Ad Hoc Networks802.11-Based Ad Hoc Networks

ABSTRACTABSTRACT

Since 2005, IEEE 802.11-based networks have been Since 2005, IEEE 802.11-based networks have been able to provide a certain level of quality of service able to provide a certain level of quality of service (QoS) by the means of service differentiation, due to (QoS) by the means of service differentiation, due to the IEEE 802.11e amendment. However, no the IEEE 802.11e amendment. However, no mechanism or method has been standardized to mechanism or method has been standardized to accurately evaluate the amount of resources accurately evaluate the amount of resources remaining on a given channel. Such an evaluation remaining on a given channel. Such an evaluation would, however, be a good asset for bandwidth-would, however, be a good asset for bandwidth-constrained applications. In multihop ad hoc constrained applications. In multihop ad hoc networks, such evaluation becomes even more networks, such evaluation becomes even more difficult. difficult.

Consequently, despite the various contributions Consequently, despite the various contributions around this research topic, the estimation of the around this research topic, the estimation of the available bandwidth still represents one of the main available bandwidth still represents one of the main issues in this field. In this paper, we propose an issues in this field. In this paper, we propose an improved mechanism to estimate the available improved mechanism to estimate the available bandwidth in IEEE 802.11-based ad hoc networks. bandwidth in IEEE 802.11-based ad hoc networks. Through simulations, we compare the accuracy of the Through simulations, we compare the accuracy of the estimation we propose to the estimation performed by estimation we propose to the estimation performed by other state-of-the-art QoS protocols, BRuIT, AAC, other state-of-the-art QoS protocols, BRuIT, AAC, and QoS-AODV.and QoS-AODV.

EXISTING SYSTEMEXISTING SYSTEM The ad hoc networking community assumes that the The ad hoc networking community assumes that the

underlying wireless technology is the IEEE 802.11 underlying wireless technology is the IEEE 802.11 standard due to the broad availability of interface standard due to the broad availability of interface cards and simulation models.cards and simulation models.

This standard has not been targeted especially for This standard has not been targeted especially for multihop ad hoc operation, and it is therefore not multihop ad hoc operation, and it is therefore not perfectly suited to this type.perfectly suited to this type.

An accurate evaluation of the capabilities of the An accurate evaluation of the capabilities of the routes is necessary. Most of the current QoS routes is necessary. Most of the current QoS proposals leave this problem aside, relying on the proposals leave this problem aside, relying on the assumption that the link layer protocols are able to assumption that the link layer protocols are able to perform such an evaluation.perform such an evaluation.

PROPOSED SYSTEMPROPOSED SYSTEM In this system we are using 802.11 MAC layer to evaluate the correct In this system we are using 802.11 MAC layer to evaluate the correct

bandwidth.bandwidth. This method combines channel monitoring to estimate each node’s This method combines channel monitoring to estimate each node’s

medium occupancy.medium occupancy. Probabilistic combination of the values is to account for Probabilistic combination of the values is to account for

synchronization between nodes, estimation of the collision synchronization between nodes, estimation of the collision probability between each couple of nodes, and variable overhead’s probability between each couple of nodes, and variable overhead’s impact estimation. impact estimation.

This mechanism only requires one-hop information communication This mechanism only requires one-hop information communication and may be applied without generating a too high additional and may be applied without generating a too high additional overhead.overhead.

We show the accuracy of the available bandwidth measurement We show the accuracy of the available bandwidth measurement through NS-2 simulations.through NS-2 simulations.

These results show that single-hop flows and multihop flows are These results show that single-hop flows and multihop flows are admitted more accurately, resulting in a better stability and overall admitted more accurately, resulting in a better stability and overall performance.performance.

MODULESMODULES

Packet CreationPacket Creation

Apply the RREQ and get RREPApply the RREQ and get RREP

Admission Control MechanismAdmission Control Mechanism

Bandwidth UtilizedBandwidth Utilized

SYSTEM REQUIREMENT SYSTEM REQUIREMENT SPECIFICATIONSPECIFICATION

Hardware RequirementsHardware Requirements Processor Processor :: Pentium IVPentium IV Hard DiskHard Disk :: 80 GB80 GB RamRam :: 1 GB1 GB

Software RequirementsSoftware Requirements Front End Front End : : Java, SwingJava, Swing Back End Back End : : MS AccessMS Access Operating System Operating System : : Windows XPWindows XP

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