Md. Mamun-Or-Rashid

Multi-Constrained QoS Geographic Routing for Heterogeneous Traffic in Sensor Networks

Sensor nodes report the sensed data packets to the sink and depending on the application these packets may have diverse attributes: time-critical (TC) and non time-critical (NTC). In such a heterogeneous traffic environment, designing a data dissemination framework that can achieve both the reliability and delay guarantee while preserving the energy efficiency, namely multi-constraint QoS (MCQoS), is a challenging problem. This paper proposes a new aggregate routing model and a localized algorithm (DARA) that implements the model. DARA is designed for multi-sink multipath location aware network architecture. Delay-differentiated multi-speed packet forwarding and in-node packet scheduling mechanisms are also incorporated with DARA. The simulation results demonstrate that DARA effectively improves the reliability, delay guarantee and energy efficiency.

Congestion Avoidance and Fair Event Detection in Wireless Sensor Network

Summary Congestion in WSN increases the energy dissipation rates of sensor nodes as well as the loss of packets and thereby hinders fair and reliable event detection. We find that one of the key reasons of congestion in WSN is allowing sensing nodes to transfer as many packets as possible. This is due to the use of CSMA/CA that gives opportunistic medium access control. In this paper, we propose an energy efficient congestion avoidance protocol that includes source count based hierarchical and load adaptive medium access control and weighted round robin packet forwarding. We also propose in-node fair packet scheduling to achieve fair event detection. The results of simulation show our scheme exhibits more than 90% delivery ratio even under bursty traffic condition which is good enough for reliable event perception. Key words: Sensor Network, Congestion Avoidance, Hierarchical Medium Access, Fair Event Detection. 1. Introduction Wireless Sensor Networks (WSNs) are densely deployed for a wide range of applications in the military, health, environment, agriculture and smart office domain. These networks deliver numerous types of traffic, from simple periodic reports to unpredictable bursts of packets triggered by sensed events. Therefore, congestion happens due to contention caused by concurrent transmissions, buffer overflows and time varying wireless channel condition [1][2][3]. As WSN is a multi-hop network, congestion taking place at a single node may diffuse to the whole network and degrades its performance drastically [4]. Congestion causes many folds of drawbacks: (i) it increases energy dissipation rates of sensor nodes, (ii) it causes a lot of packet loss, which in turn diminish the network throughput, and (iii) it hinders fair event detections and reliable data transmissions. Therefore, congestion avoidance and fair packet delivery become a crucial research issue for the practical realization of WSN based envisioned applications.

Reliable event detection and congestion avoidance in wireless sensor networks

Due to dense deployment and innumerable amount of traffic flow in wireless sensor networks (WSNs), congestion becomes more common phenomenon from simple periodic traffic to unpredictable bursts of messages triggered by external events. Even for simple network topology and periodic traffic, congestion is a likely event due to time varying wireless channel condition and contention caused due to interference by concurrent transmissions. Congestion causes huge packet loss and thus hinders reliable event perception. In this paper, we present a congestion avoidance protocol that includes source count based hierarchical medium access control (HMAC) and weighted round robin forwarding (WRRF). Simulation results show that our proposed schemes avoid packet drop due to buffer overflow and achieves more than 90% delivery ratio even under bursty traffic condition, which is good enough for reliable event detection.

Energy-aware QoS provisioning for wireless sensor networks: Analysis and protocol

Wireless sensor networks (WSNs) are envisioned to facilitate information gathering for various applications and depending on the application types they may require certain quality of service (QoS) guarantee for successful and guaranteed event perception. Therefore, QoS in WSNs is an important issue and two most important parameters that hinder the goal of guaranteed event perception are time-sensitive and reliable delivery of gathered information, while a minimum energy consumption is desired. In this paper, we propose an energy-aware, multi-constrained and multi-path QoS provisioning mechanism for WSNs based on optimization approach. Hence, a detailed analytical analysis of reliability, delay and energy consumption is presented to formulate the optimization problem in an analytical way. A greedy algorithm is proposed to achieve the desired QoS guarantee while keeping the energy consumption minimum. Also, a simple but efficient retransmission mechanism is proposed to enhance the reliability further, while keeping the delay within delay bound. Simulation results demonstrate the effectiveness of our scheme.

Cost-effective maximum lifetime routing protocol for wireless sensor networks

Wireless sensor networks are composed of a high number of very simple nodes where most of them have to perform the function of a router. Energy consumption of these nodes is important as power is supplied to the nodes by limited batteries, which circumscribe the lifetime of the links as well as the whole network. Some of the recent routing protocols are greedy on network lifetime by balancing the remaining energies among the nodes in the networks. Although, these algorithms help to maintain the stability of the network, they are not as cost effective as existing traditional routing algorithms. Our proposed method makes a tradeoff between the routing cost and network lifetime issues in route selection, and ensures a good compromise between these two conflicting interests.

Energy Conserving Passive Clustering for Efficient Routing in Wireless Sensor Network

In case of sensor network, hierarchical routing has received a great magnitude of interest than flat routing for achieving energy efficiency. While the overhead of creating hierarchical control structure, should be kept reasonably low. Directed diffusion (DD) is one of the most prominent and widely accepted example of hierarchical data centric routing. Directed diffusion suffers from huge flooding problem and further improved using passive clustering to reduce flooding for interest propagation. Passive clustering technique is not energy efficient as it does not consider residual energy of nodes. Also it does not have any parameter to restrict the number of clusterheads and gateways. To achieve energy efficiency and prolonged network lifetime we introduce residual energy and distance based cluster creation. Energy conserving passive clustering technique will select better nodes as clusterhead and gateway in terms of residual energy and distance which will in turn reduce the overlapping region and number of gateway to conserve energy. At the same time we have applied periodic sleep and awake among cluster members to achieve prolonged lifetime. Our proposed algorithm will add some extra overhead for cluster creation and maintenance in compare to passive clustering but will perform better in terms of energy dissipation and enhanced lifetime of the network.

Passive cluster based clock synchronization in sensor network

Clock synchronization has been paid great attention in distributed systems. Sensor networks differ from traditional distributed systems in many ways. One of the dramatic differences is the energy constraint in sensor networks which is absent in traditional distributed systems. Almost any form of sensor data fusion or coordinated actuation requires synchronized physical time for reasoning about events in the physical world. Sensor networks make extensive use of time synchronized operations in many contexts (for example TDMA schedulers, synchronized sleep period, tracking and surveillance application). In this paper we propose a novel scheme for clock synchronization in sensor networks which is a combined idea of passive clustering and diffusion based asynchronous averaging algorithm for clock synchronization. Our proposed scheme takes the advantage of passive clustering for cluster creation and then applies the asynchronous averaging algorithm for clock synchronization to reduce number of rounds and operations required for converging time which in turn save significantly more energy than the energy required in the diffusion based asynchronous averaging algorithm.

WSNMP: A Network Management Protocol for Wireless Sensor Networks

Wireless sensor networks are uniquely characterized by their limited resources and are deployed in remote and hostile environments. These highly dynamic networks are very prone to failure and are usually kept unattended. Therefore, proper management of WSN and its limited resources is highly desirable for an effective and efficient functioning of the network. In this paper, we propose WSNMP, a low overhead, hierarchical wireless sensor network management protocol. The proposed mechanism provides the methods to monitor the network states by collecting management data and accordingly control and maintain the network resources.

A Channel Management Framework to Construct User Preferred Fast Channel Change Stream in IPTV

This paper proposes an effective channel management framework which analyzes the user channel surfing behavior and constructs fast channel change stream consisting of user preferred channels. The usual channel delay is obliterated if the user requested channel is found at the Set-Top-Box (STB).

Aggregated traffic flow weight controlled hierarchical MAC protocol for wireless sensor networks

It has been discussed in the literature that the medium-access control (MAC) protocols, which schedule periodic sleep–active states of sensor nodes, can increase the longevity of sensor networks. However, these protocols suffer from very low end-to-end throughput and increased end-to-end packet delay. How to design an energy-efficient MAC protocol that greatly minimizes the packet delay while maximizing the achievable data delivery rate, however, remains unanswered. In this paper, motivated by the many-to-one multihop traffic pattern of sensor networks and the heterogeneity in required data packet rates of different events, we propose an aggregated traffic flow weight controlled hierarchical MAC protocol (ATW-HMAC). We find that ATW-HMAC significantly decreases the packet losses due to collisions and buffer drops (i.e., mitigates the congestion), which helps to improve network throughput, energy efficiency, and end-to-end packet delay. ATW-HMAC is designed to work with both single-path and multipath routing. Our analytical analysis shows that ATW-HMAC provides weighted fair rate allocation and energy efficiency. The results of our extensive simulation, done in ns-2.30, show that ATW-HMAC outperforms S-MAC; traffic-adaptive medium access; and SC-HMAC.