08-03-2011, 10:19 AM
Presented by:
Amit Agrawal
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Wireless LAN Simulation- IEEE 802.11 MAC Protocol
Project Goals
• MATLAB simulation
- DCF (Distributed Coordination Function)
- No Propagation Delay
• Performance Analysis
- Number of Nodes
- Range
- Packet Size
- RTS/CTS
DCF
• DCF
- CSMA/CA is a DCF
• Salient features
- Medium sharing through CSMA/CA
- Allows one to use the medium
- Random Back off interval before retransmission
- Refinement – RTS/CTS packets
IEEE 802.11 MAC Protocol
• Also known as CSMA/CA
• 802.11 CSMA
Sender
If the channel is idle for DIFS seconds
- Transmit DATA packet
If the channel is busy
- Backoff
Receiver
If DATA packet received
- Return ACK after SIFS seconds
IEEE 802.11 MAC Protocol
MATLAB Simulation
• Old Simulation
- Implemented CSMA (No RTS/CTS)
• New Simulation
- Includes RTS/CTS exchange
- Simulates CSMA/CA
Analysis
Strengths/Weaknesses
• Strengths
- Fairly accurate simulation of CSMA/CA
- Fewer packet collisions and more successful transmissions evident
• Drawbacks of our simulation
- Cluttered simulation window
- Deadlocks increase with more nodes