PACE: Simple Multi-hop Scheduling for Single-radio 802.11-based Stub Wireless Mesh Networks

IEEE 802.11-based Stub Wireless Mesh Networks (WMNs) are a cost-effective and flexible solution to extend wired network infrastructures. Yet, they suffer from two major problems: inefficiency and unfairness. A number of approaches have been proposed to tackle these problems, but they are too restrictive, highly complex, or require time synchronization and modifications to the IEEE 802.11 MAC. PACE is a simple multi-hop scheduling mechanism for Stub WMNs overlaid on the IEEE 802.11 MAC that jointly addresses the inefficiency and unfairness problems. It limits transmissions to a single mesh node at each time and ensures that each node has the opportunity to transmit a packet in each network-wide transmission round. Simulation results demonstrate that PACE can achieve optimal network capacity utilization and greatly outperforms state of the art CSMA/CA-based solutions as far as goodput, delay, and fairness are concerned

Effectiveness Analysis of Physical Carrier-sensing in IEEE 802.11 Wireless Networks

[[abstract]]Abstract: Physical carrier-sensing mechanism has been used as an effective way to alleviate interference in wireless networks, but it also constrains spatial reuse. The aggregate throughput in wireless ad hoc networks is a tradeoff between spatial reuse and interference avoidance. The influence of physical carrier-sensing on the aggregate network throughput has attracted several studies. Previous work investigated the interference with the packet reception at receivers and proposed the optimal carrier-sensing range to achieve the maximum aggregate throughput. However, the interference with the sender’s reception of the receiver’s acknowledgement (ACK) has been ignored. In this paper, we consider the influence of interference at both senders and receivers on the aggregate throughput in wireless ad hoc networks. We propose a spatiotemporal model that describes the effectiveness of the physical carrier-sensing mechanism.[[conferencetype]]國內[[conferencedate]]20120601~2012060

Protecting 802.11-Based Wireless Networks From SCTS and JACK Attacks

The convenience of IEEE 802.11-based wireless access networks has led to widespread deployment. However, these applications are predicated on the assumption of availability and confidentiality. Error-prone wireless networks afford an attacker considerable flexibility to exploit the vulnerabilities of 802.11-based mechanism. Two of most famous misbehaviors are selfish and malicious attacks. In this thesis we investigate two attacks: Spurious CTS attack (SCTS) and Jamming ACK attack (JACK). In the SCTS, malicious nodes may send periodic Spurious CTS packets to force other nodes to update their NAV values and prevent them from using the channel. In the JACK, an attacker ruins legitimate ACK packets for the intention of disrupting the traffic flow and draining the battery energy of victim nodes quickly. Correspondingly, we propose solutions: termed Carrier Sensing based Discarding (CSD), and Extended Network Allocation Vector (ENAV) scheme. We further demonstrate the performance of our proposed schemes through analysis and NS2 simulations

Protecting 802.11-Based Wireless Networks From SCTS and JACK Attacks

The convenience of IEEE 802.11-based wireless access networks has led to widespread deployment. However, these applications are predicated on the assumption of availability and confidentiality. Error-prone wireless networks afford an attacker considerable flexibility to exploit the vulnerabilities of 802.11-based mechanism. Two of most famous misbehaviors are selfish and malicious attacks. In this thesis we investigate two attacks: Spurious CTS attack (SCTS) and Jamming ACK attack (JACK). In the SCTS, malicious nodes may send periodic Spurious CTS packets to force other nodes to update their NAV values and prevent them from using the channel. In the JACK, an attacker ruins legitimate ACK packets for the intention of disrupting the traffic flow and draining the battery energy of victim nodes quickly. Correspondingly, we propose solutions: termed Carrier Sensing based Discarding (CSD), and Extended Network Allocation Vector (ENAV) scheme. We further demonstrate the performance of our proposed schemes through analysis and NS2 simulations