Efficient Cross Layer Designs for IEEE 802.11 Wireless Networks

Numerous attributes of wireless networks, like mobility, frequent disconnections and varying channel conditions, have made it a tough task to develop networking protocols for wireless communications. In this report, we deal with numerous issues associated with both the routing layer and medium access control (MAC) layer in wireless networks hoping to improve the network performance. Initially, we study the effect of the channel noise on the network performance. We offer mechanisms to compute energy-efficient paths in noisy environments for ad hoc networks by exploiting the IEEE 802.11 fragmentation mechanism. These mechanisms improve the network performance up to orders of magnitude when it comes to energy and throughput. Furthermore, improve the IEEE 802.11 infrastructure networks with a capability to differentiate between various kinds of unsuccessful transmissions to boost the network performance. Second, we examine the outcomes of the physical layer capture phenomena…


1 Introduction
1.1 Characteristics of Wireless Network
1.2 Cross-Layer Design
1.3 Contributions of the Dissertation
1.3.1 Wireless Networks in Noisy Environments
1.3.2 Physical Layer Capture Effect
1.3.3 Directional Antennas
1.4 Structure of the Dissertation
2 Background
2.1 IEEE 802.11 Standard
2.1.1 IEEE 802.11 Distributed Coordination Function (DCF)
2.1.2 IEEE 802.11 Fragmentation
2.2 Radio Propagation Model
2.2.1 Free Space/Two-ray Propagation Model
2.2.2 Capture Effect
2.3 Directional Antenna
3 Efficient Ad Hoc Routing Protocols in Noisy Environments
3.1 Related Work
3.2 Wireless Link Error Rates
3.3 Optimal Fragment Size for Energy Efficient Paths
3.4 AODV and its Proposed Modifications
3.4.1 Link Error Rates Estimation
3.4.2 Messages and Structures of AODV
3.4.3 Route Discovery
3.5 Performance Evaluation
3.5.1 Network Topology and Link Error Modeling
3.5.2 Metrics
3.5.3 Static Grid Topologies
3.5.4 Static Random Topologies
3.5.5 Mobile Topologies
3.6 Conclusion
4 Analyzing and Enhancing the IEEE 802.11 DCF in Noisy Environments
4.1 Related Work
4.2 Markov Chain Model of the IEEE 802.11 DCF in Noisy Environment
4.3 Model Validation
4.4 smartBEB: Enhanced IEEE 802.11 MAC
4.5 Implementation of smartBEB Mechanism
4.5.1 RTS/CTS Access Mode
4.5.2 Basic Access Mode
4.6 IEEE 802.11 fairness in Noisy environments
4.6.1 Conclusion
5 LED: Location Enhancement for the IEEE 802.11 Distributed Coordination Function
5.1 Related Works
5.2 Performance of Capture Effect in 802.11 Networks
5.2.1 Inefficiency of Carrier Sense Mechanism
5.2.2 Probability of Non-interfering Transmission
5.3 Location Enhanced DCF Protocol
5.3.1 Protocol Overview
5.3.2 Physical Layer Design
5.3.3 MAC Layer Design
5.4 Performance Evaluation
5.4.1 Simulation Environment
5.4.2 Impact of Node Density
5.4.3 Impact of Network Load
5.4.4 Impact of Network Degree
5.4.5 Capture Factor β
5.4.6 Impact of Errors in Node Locations
5.4.7 Impact of Transmission and Carrier Sense Range
5.4.8 Experimenting with Infrastructure Networks
5.5 Conclusion
6 Opportunistic Mechanisms for IEEE 802.11 Networks using Directional An-tennas I:
Opportunistic Carrier Sense Transmission
6.1 Related Works
6.2 Problem Formulation
6.3 Analysis of Blocking Probabilities with OPPCS
6.3.1 Model Assumption
6.3.2 Analysis of OPPCS Probability
6.3.3 Verification of OPPCS Model
6.4 Implementation of OPPCS
6.4.1 Physical Layer Design
6.4.2 MAC Layer Design
6.5 Performance Evaluation
6.5.1 Impact of Network Degree
6.5.2 Impact of network load
6.5.3 Impact of Beamwidth Size
6.5.4 Impact of Transmission and Carrier Sense Range
6.6 Conclusion
7 Opportunistic Mechanisms for IEEE 802.11 Networks using Directional An-tennas II:…..

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