Managing contention with medley +91-9994232214,8144199666, ieeeprojectchennai@gmail.com, www.projectsieee.com, www.ieee-projects-chennai.com IEEE PROJECTS 2015-2016 ----------------------------------- Contact:+91-9994232214,+91-8144199666 Email:ieeeprojectchennai@gmail.com Support: ------------- Projects Code Documentation PPT Projects Video File Projects Explanation Teamviewer Support

1. Managing Contention with Medley
Abstract:
As WLANs achieve gigabit per second speeds, they will need to support
users with a wide range of workloads, ranging from VoIP and Web clients
to data backup, file transfers, and streaming high-definition video.
Unfortunately, channel efficiency degrades severely in these scenarios
under existing MAC protocols due to contention and back-off overheads.
Moreover, small yet latency sensitive flows suffer disproportionally as load
increases. We present Medley, a system that leverages frequency-based
contention to allocate sub channels in an OFDMA-based link layer in a
delay-fair manner. In contrast to traditional CSMA schemes in which each
node competes uniformly for the channel, Medley ensures that nodes with
smaller service rates are served before those with heavier demand; the
more bandwidth a node consumes, the larger its packet average delay will
become. An initial implementation of Medley on a software defined radio
platform demonstrates its feasibility in a small network, while more
comprehensive simulation results show its benefits under a wider range of
conditions. Medley delivers delay fairness while remaining over 94 percent
efficient in the face of massive over-subscription.

2. Existing System:
We argue that the fundamental deficiency of 802.11 and related
technologies lies in their fairness model—or, rather, lack thereof. In
particular, nodes in these networks compete equally for the channel during
each contention opportunity: nodes with huge bandwidth demands but no
delay requirements (e.g., file transfers or buffered multimedia streaming)
are as likely to win the channel as nodes that only rarely request channel
access, but need low latency when they do, such as VoIP or gaming flows.
We introduce Medley, an OFDMA-based channel access scheme that
provides transparent service differentiation. Rather than explicitly
prioritize certain nodes or traffic flows, Medley implements what we call
delay fairness: packets from flows with smaller service rates are served
before those from higher service rates. Medley’s design addresses three
distinct but interrelated problems.
Proposed System:
First, nodes must be able to efficiently express a wide range of demands.
Medley’s multitone RTS/CTS (M-RTS) mechanism supports large numbers
of competing nodes by employing a compact demand encoding and
dynamically scaling the amount of demand nodes may express.

3. Second, to accurately estimate demand during periods of over-
subscription, Medley apportions signaling resources (i.e., M-RTS
subcarriers) appropriately to nodes that are most deserving of allocations.
Finally, delay fairness requires the AP to approximate the service rate of
each node contending for the channel. Inspired by the multi-level
UNIX scheduler, Medley employs an adaptive token bucket based
approximation scheme to classify nodes into a fixed set of categories that
determine how to service their instantaneous demands.
Hardware Requirements:
• System : Pentium IV 2.4 GHz.
• Hard Disk : 40 GB.
• Floppy Drive : 1.44 Mb.
• Monitor : 15 VGA Colour.
• Mouse : Logitech.
• RAM : 256 Mb.
Software Requirements:
• Operating system : - Windows XP.
• Front End : - JSP
• Back End : - SQL Server

4. Software Requirements:
• Operating system : - Windows XP.
• Front End : - .Net
• Back End : - SQL Server