S.M. Sadakatul Bari

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 novel spiral back-off mechanism for wireless sensor networks MAC protocol in smart grid system

Wireless sensor networks are considered as the enabling technology for multiple smart grid applications such as remote metering, direct load control, renewable energy integration, substation monitoring etc. The IEEE 802.15.4 standard provides a basic foundation by defining the physical and MAC layer of the low power wireless sensor network. Carrier Sense Multiple Access-Collision Avoidance (CSMA-CA) with binary exponential backoff (BEB) algorithm is used as a technique to share the common wireless medium and avoids collision among the contending sensor nodes. However, this binary exponential algorithm does not account the application of traffic characteristics that essentially negatively affects the smart grid network performances in terms of packet delivery ratio and the time delay. In this paper, a novel spiral backoff mechanism is proposed that has considered the applications of traffic type to improve the network performances. Simulation results show that proposed spiral backoff algorithm reduces the end-to-end delay and increases packet delivery ratio (PDR) for the smart grid wireless sensor networks.

Improved link repair technique for multicast routing in Wireless Mesh Network

Efficient multicasting over Wireless Mesh Network (WMN) is challenging due to dynamic and multi-hop wireless communication among multicast group members. Multicast Ad hoc On-Demand Distance Vector (MAODV) protocol is a tree based multicast routing protocol that enables dynamic, self-starting, multi-hop routing between participating mobile nodes wishing to join or participate in a multicast group in Wireless Mesh Network (WMN). The mobility of mobile nodes often causes link breakage in the tree-based protocols which sometime results in tree partitioning and poor performance. In MAODV, when a broken link is detected between two nodes on the multicast tree, the node downstream to the break is responsible for initiating the repair of the broken link. After link repair, it is likely that the previous distance between the nodes (nodes downstream to the link breakage) and the group leader will not remain same. The shortest path from the group leader to the nodes downstream to the node which initiates link breakage is not ensured. Moreover, if the node attempting to repair a tree link break does not receive a response after certain attempts, it assumes that the multicast tree is not repairable currently and this leads to tree partitioning. In this paper, an improved link repair technique is proposed which ensures shortest path from any node to the group leader. Simulation results demonstrate significant improvement in performance metrics compared to standard MAODV.

Traffic Aware Wireless Sensor Networks MAC Protocol for Smart Grid Applications Using Spiral Backoff Mechanism

IEEE 802.15.4 standard provides a low cost, low power wireless sensor network solution for smart grid communication networks. This standard uses slotted Carrier Sense Multiple Access-Collision Avoidance (CSMA-CA) with binary exponential back off algorithm (BEB) to avoid collision between the sensor nodes. However, BEB does not consider the traffic characteristics which degrade the smart grid network performance. In this paper, a traffic aware spiral back off mechanism is proposed to improve the network performance. Simulation results show that proposed spiral back off algorithm reduces the end-to-end delay and increase packet delivery ratio (PDR) for real time data.

A Review on Channel Access Control Mechanism to Improve the Dependability in Body Area Networks

The Body Area Networks (BANs) are quick growth to develop e-health care system for monitoring to various patients and are convenient and accessible for both patients and physicians. Many researchers are focused on different area like-signal processing, biosensor design, power efficiency and so on in BANs. However, still numerous issues are plagued in BANs to development and implementation effectively at present. One of these is to increase dependability which includes-reliability, security, availability etc from both communication perspectives intra and extra BAN. This review paper aims to investigate the exist BANs and highlights the merits and demerits of the current BANs. In addition, the proposed paper displays the challenges of present BANs and proposed a mechanism to improve the dependability of BANs.