Improving IEEE 802.11g Mac to Support Quality of Service for Multimedia Applications in Wireless Networks

This paper paper investigates, describes and propose better techniques to provide QoS by assigning new metrics to the DCF access method, involving the DCF Interframe Space (DIFS), Contention Window values and the maximum data packet size to high priority nodes, which will bias towards high priority multimedia traffic to support QoS. A simulation is done using Network Simulator 2 (NS-2) and comparisons were made between different sets of network simulation scenarios. Improvements on throughput, delay and jitter can clearly be seen and further analysis is then presented

Improving IEEE 802.11 to Support Quality of Service in Wireless Networks

This paper investigates and describes the Quality of Services (QoS) provisioning techniques for IEEE 802.11 based networks, focusing on the Distributed Coordination Function (DCF). This paper propose better techniques to provide QoS by assigning new parameters to the DCF access method, involving the DCF Interframe Space (DIFS), backoff time and the maximum data packet size to high priority nodes, which will distinguish the high priority traffic from the low priority traffic to support QoS. A simulation is done using Network Simulator 2 (NS-2) and the expected output is then presented

Achieving Stable Throughput to Support QoS in IEEE 802.11 Wireless Networks

This paper investigates and describes a new provisioning technique for IEEE 802.11 based networks, focusing on the ad-hoc Distributed Coordination Function (DCF) to redefine stability of the network throughput to support QoS. This paper propose better techniques to achieve stable throughput in Wireless LAN networks by assigning new values to the Contention Window to high priority traffics which will guarantee better throughput to the selected network traffic. A simulation is done using Network Simulator 2 (NS-2) and findings are then presented. Results showed that stable throughput can be achieved to provide better traffic flows especially for real-time traffic and multimedia applications

A Novel Approach on Teaching Network Security for ICT Courses

This paper discusses a curriculum approach that will give emphasis on practical sessions of teaching network security subjects in information and communication technology courses. As we are well aware, the need to use a practice and application oriented approach in education is paramount [1]. Research on active learning and cooperative groups showed that students grasps and have more tendency towards obtaining and realizing soft skills like leadership, communication and team work as opposed to learning using the traditional theory and exam based method. While this teaching and learning paradigm is relatively new in Malaysia, it has been practiced widely in the West. This paper examines a particular approach whereby students learning wireless security are divided into small manageable groups consisting of black hat and white hat team. The former will try to find and expose vulnerabilities in a wireless network while the latter will try to prevent such attacks on their wireless networks using hardware, software, design and enforcement of security policy and etc. This paper will try to demonstrate whether this approach will result in a more fruitful outcome in terms of students concept and theory understandings and motivation to learn

Performance Enhancements in IEEE 802.11 DCF MANET through Variation of SIFS Values in Distance Vector Routing Environment

This paper describes and investigates the performance enhancement techniques used in IEEE 802.11g MANET in AODV and DSDV routing environment. Through variation of Short Interframe Space (SIFS) values, a better scheme to enhance the wireless network performance can be achieved. This is important especially to assign high priority network nodes that carry time sensitive data to reach the intended receiver in a timely manner. Using NS-2, network simulations are done and the findings are presented. It is showed that nodes using the variated SIFS values can achieve higher throughput compared to nodes using the default SIFS values

Topology influence on TCP congestion control performance in multi-hop ad hoc wireless

Wireless ad hoc nodes are freely and dynamically self-organize in communicating with others.Each node can act as host or router.However it actually depends on the capability of nodes in terms of its current power level, signal strength, number of hops, routing protocol, interference and others.In this research, a study was conducted to observe the effect of hops count over different network topologies that contribute to TCP Congestion Control performance degradation.To achieve this objective, a simulation using NS-2 with different topologies have been evaluated.The comparative analysis has been discussed based on standard observation metrics: throughput, delay and packet loss ratio.As a result, there is a relationship between types of topology and hops counts towards the performance of ad hoc network.In future, the extension study will be carried out to investigate the effect of different error rate and background traffic over same topologies

Retransmission-Based Additional TXOP Allocation for Audio-Video Transmission by IEEE 802.11e HCCA

This paper proposed a method of allocating additional TXOP duration to replenish the bandwidth used during the retransmission of frames at link layer in audio-video transmission by IEEE 802.11e HCCA. In the proposed scheme, the HC monitors the number of retransmission at link layer and utilize the surplus bandwidth to allocate additional TXOP duration on the basis of number of retransmission performed during the last transmission. The proposed scheme also reduces the polling overhead to gain surplus bandwidth by polling only a station in a polling interval. By simulation, we compare the application-level QoS of the TGe scheme and the proposed scheme. Numerical results show that the proposed scheme can keep the QoS of audio and video high under lossy wireless channel especially when the number of multimedia stations is small. Furthermore, the proposed scheme can admit more traffic flows than the TGe scheme