M. H. Masud

Performance study of hybrid Wireless Mesh Protocol (HWMP) for IEEE 802.11s WLAN mesh networks

Wireless Mesh Network (WMN) have been envisioned as an important solution to the next generation wireless networking which can be used in wireless community networks, wireless enterprise networks, transportation systems, home networking and last-mile wireless internet access. Many proprietary mesh solutions were developed by individual vendor but in order to interoperability; IEEE forms a task group called IEEE 802.11s to develop an integrated mesh networking solution. Hybrid Wireless Mesh protocol (HWMP) and airtime metrics as default routing protocol and routing metrics set by the task group. There is few test bed and many simulation studies have been done to evaluate the performance of the HWMP protocol with the assumption of unique type of flow with fixed packet size and packet rate. However, real networks carry a diverse application (video, voice, FTP, Email etc) with different characteristics (packet size, data rate). In this paper, we are investigated and analyzed the performance of HWMP protocol under such heterogeneous application characteristics.

Enhancement of handoff latency reduction mechanism of mobile internet protocol version 6 (MIPv6)

MIPv6 is envisioned for next generation networks to achieve ubiquitous and seamless communications for its wide address spaces and many additional features. However, MIPv6 is not widely deployed due to handoff latency and other limitations leading to packet loss and Quality of Service (QoS) degradation for real time applications such as audio and video streaming. MIPv6 handoff latency can be categorized into layer 2 (L2) and layer 3 (L3) delays that includes link layer establishment delay, movement detection delay, address configuration delay and binding update or registration delay. Movement detection delay and address configuration including Duplicate Address Detection (DAD) in layer 2 and layer 3 respectively consume the highest time of the total delay. Therefore, an optimal solution is needed to reduce the delays in both layers. In order to reduce these handoff latencies, two solutions are proposed to focus all the delays both in L2 and L3. The first solution is the fuzzy logic technique based network awareness to reduce movement detection delay especially the scanning time in layer 2 in heterogeneous networks. The second solution is parallel DAD (PDAD) to reduce address configuration time in layer 3. Both solutions benchmarked with OMNeT++ simulator show improvements over standard MIPv6 networks. The overall handoff reduced from 1300ms to 500ms applying fuzzy logic technique at L2 and PDAD mechanism in L3 that combines 60% improvements.

A Parallel Duplicate Address Detection (PDAD) mechanism to reduce handoff latency of Mobile Internet Protocol version 6 (MIPv6)

Next Generation Networks (NGN) are envisioned to be fully Internet Protocol (IP) based so that users can experience high quality and ubiquitous communication. In order to realize this, Internet Engineering Task Force (IETF) is taking advantage of Mobile Internet Protocol version 6 (MIPv6) because it has more suitable features than MIPv4. However, MIPv6 is not widely deployed due to handoff latency and other limitations. This causes packet loss and degrades the Quality of Service (QoS) for real-time applications. MIPv6 handoff latency includes link layer establishment delay, movement delay, address auto-configuration delay and binding update/registration delay. Duplicate Address Detection (DAD) is performed during address auto-configuration which takes around 70% of the time for the total handoff procedures. In order to reduce this handoff latency, a Parallel DAD (PDAD) model is proposed for reducing packet loss. The key idea behind this model is that a Mobile Node (MN) solicits for a router advertisement (RA) in parallel to its neighbor routers before leaving the previous point of attachment.

A review on scheduling schemes of high speed Wireless Campus Network for Interactive Multimedia transmission

Interactive Multimedia (IMM) offers voice, video conferencing, graphics services at low cost with more flexibility in a high speed Wireless Local Area Network (WLAN) that can be defined as a high speed Wireless Campus Network (WCN). In a video or voice conversation, the direction of traffic flow over the networks defines the participating users work either as a sender or a receiver. In order to improve performance of IMM traffic in WCN, data loss has to be kept minimum with maximum throughput. Packets scheduling is one of the challenging issues for improving IMM transmission and it is still an unresolved problem over WCN. This work aims to explain the fundamental characteristics of IMM related to various applications and highlights the present scheduler issues. A new scheduling scheme has been proposed which is expected to deliver the optimum Quality of Service (QoS) with the least handoff delay and call dropping probabilities for IMM applications though WCNs.

Fuzzy Logic based Handoff Latency Reduction Mechanism in Layer 2 of Heterogeneous Mobile IPv6 Networks

Mobile IPv6 (MIPv6) is one of the pioneer standards that support mobility in IPv6 environment. It has been designed to support different types of technologies for providing seamless communications in next generation network. However, MIPv6 and subsequent standards have some limitations due to its handoff latency. In this paper, a fuzzy logic based mechanism is proposed to reduce the handoff latency of MIPv6 for Layer 2 (L2) by scanning the Access Points (APs) while the Mobile Node (MN) is moving among different APs. Handoff latency occurs when the MN switches from one AP to another in L2. Heterogeneous network is considered in this research in order to reduce the delays in L2. Received Signal Strength Indicator (RSSI) and velocity of the MN are considered as the input of fuzzy logic technique. This technique helps the MN to measure optimum signal quality from APs for the speedy mobile node based on fuzzy logic input rules and makes a list of interfaces. A suitable interface from the list of available interfaces can be selected like WiFi, WiMAX or GSM. Simulation results show 55% handoff latency reduction and 50% packet loss improvement in L2 compared to standard to MIPv6.

Performance analysis of IIUM wireless campus network

International Islamic University Malaysia (IIUM) is one of the leading universities in the world in terms of quality of education that has been achieved due to providing numerous facilities including wireless services to every enrolled student. The quality of this wireless service is controlled and monitored by Information Technology Division (ITD), an ISO standardized organization under the university. This paper aims to investigate the constraints of wireless campus network of IIUM. It evaluates the performance of the IIUM wireless campus network in terms of delay, throughput and jitter. QualNet 5.2 simulator tool has employed to measure these performances of IIUM wireless campus network. The observation from the simulation result could be one of the influencing factors in improving wireless services for ITD and further improvement.

The impact of randomness on high speed Wireless Campus Network in IEEE802.11e

The enhancement of channel access mechanism assures to provide Quality of Service (QoS) using the service differentiation mechanism over WLAN in IEEE802.11e. The service differentiation scheme is used in the Enhanced Distributed Channel Access (EDCA) MAC layer protocol and this protocol is used the random back-off window algorithm to provide QoS for the real time multimedia applications. However, the back-off window mechanism ensures QoS to satisfy multimedia traffic but it only the probabilistic QoS due to the random nature of the algorithm. As like as the randomness of the mobility models that can be reduced the network performance. In this paper, we analyze the proposed network performance based on the variation of randomness using different seed values and evaluate the network performance using various performance metrics in IEEE802.11e.

A comprehensive analysis of improving QoS and IMM traffic of high speed wireless campus network

Interactive Multimedia (IMM) applications such as voice and video conferencing are very important in our learning environment. They offer useful services that benefit its users but these services suffers performance degradation from todays high speed Wireless Local Area Network (WLAN). However, guaranteed Quality of Service (QoS) remains the bottleneck in the network which becomes a great challenge in attempting to improve its performance. This work reviewed many approaches and considers mapping QoS class parameters such as Quality of Service Class Identifier (QCI), Maximum Bit Rate (MBR) and Allocation and Retention Priority (ARP) to the upstream and downstream data flowing in the network as an attempt to improve its performance. Priority is then given to the QoS bearer packets by associating Differentiated Services Code Point (DSCP). A comprehensive analysis of QoS in different protocols in wireless networks has been studied. Open issues and research directions have been addressed with a proposed mechanism to enhance the QoS of the wireless network.

An analysis of resource sharing scheme in heterogeneous wireless campus network

The next generation wireless technology systems are being devised with the vision of heterogeneity where a Multimode Device (MD) would be connected with multiple wireless networks like GSM, WiFi, and WiMAX. Bandwidth is one of the main resources of these technologies which is operated independently that need to be aggregated among these technologies in Heterogeneous Wireless Network (HWN). This paper aims to investigate the issues of campus based heterogeneous wireless network, its benefits and challenges. It has been found that an efficient scheduling model for packet reordering and an appropriate interface selection mechanism are important for HWN. Besides its benefits, this paper also addresses the schemes including genetic algorithm, fuzzy logic technique and game theory those have been using for bandwidth allocation. Finally, this paper proposes a mechanism for bandwidth allocation in a HWN environment.