Bandwidth Estimation for IEEE 802-11-Based Ad Hoc Networks(2008)

Abstract:

Since 2005, IEEE 802.11-based networks have been able to provide a certain level of quality of service (QoS) by the means of service differentiation, due to the IEEE 802.11e amendment. However, no mechanism or method has been standardized to accurately evaluate the amount of resources remaining on a given channel. Such an evaluation would, however, be a good asset for bandwidth-constrained applications. In multihop ad hoc networks, such evaluation becomes even more difficult. Consequently, despite the various contributions around this research topic, the estimation of the available bandwidth still represents one of the main issues in this field. In this paper, we propose an improved mechanism to estimate the available bandwidth in IEEE 802.11-based ad hoc networks. Through simulations, we compare the accuracy of the estimation we propose to the estimation performed by other state-of-the-art QoS protocols, BRuIT, AAC, and QoS-AODV.

Existing System:

Ø  The ad hoc networking community assumes that the underlying wireless technology is the IEEE 802.11 standard due to the broad availability of interface cards and simulation models.

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

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

Proposed System:

Ø  In this system they are using 802.11 MAC layer to evaluate the correct bandwidth.

Ø  This method combines channel monitoring to estimate each node’s medium occupancy.

Ø  Probabilistic combination of the values is to account for synchronization between nodes, estimation of the collision probability between each couple of nodes, and variable overhead’s impact estimation.

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

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

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

System Requirements

Hardware:

PROCESSOR      :  PENTIUM IV 2.6 GHz

RAM                      :    512 MB DD RAM

MONITOR            :    15” COLOR

HARD DISK         :    20 GB

FLOPPY DRIVE   :     1.44 MB

CDDRIVE              :    LG 52X

KEYBOARD         :     STANDARD 102 KEYS

MOUSE                 :    3 BUTTONS

Software:

Front End              :  Java, Swing

Back End               :  MS Access

Tools Used            :  JFrameBuilder

Operating System  :  WindowsXP

Modules

Ø  Packet creation

Ø  Apply the RREQ And get RREP

Ø  Admission Control Mechanism

Ø  Utilized Bandwidth

Module Description

Packet Creation

            In this module we split the Data in to N number of Fixed size packet with Maximum length of 48 Characters.

Apply the RREQ and get RREP

            The aim of the RREQ is to find a route between the sender and the receiver that meets the constraints specified by the application level in terms of Bandwidth. Therefore, two flows with the same source and destination can follow different routes depending on the network state.

            When a source node has data to send, it broadcasts a route request (RREQ) to its neighbors. The RREQ packet contains the address of the sender, and the requirements at the application level, the destination address, and a sequence number. The Intermediate Node or Destination Node sends RREP if it is free, otherwise, it silently discards the message.

Admission Control Mechanism

            The Admission Control Mechanism is done in the receiver side. The Admission Control Mechanism has the all status of the node so if the nodes want to send RREP or discard the message, the particular node check the status by using the Admission Control Mechanism.

Bandwidth Utilized

            After the source nodes send the total message to the Destination Node finally we calculate the end to end delivery of the Bandwidth and Time delay.

In module given input and expected output

            The source node selects the destination node first and then by using the browse button we select some text file and this text file is send to the destination side.