Energy-efficient cluster-based dynamic routes adjustment approach for wireless sensor networks with mobile sinks

This paper proposes a framework to maximize the lifetime of the wireless sensor networks (WSNs) by using a mobile sink when the underlying applications tolerate delayed information delivery to the sink. Within a prescribed delay tolerance level, each node does not need to send the data immediately as it becomes available. Instead, the node can store the data temporarily and transmit it when the mobile sink is at the most favorable location for achieving the longest WSN lifetime. To find the best solution within the proposed framework, we formulate optimization problems that maximize the lifetime of the WSN subject to the delay bound constraints, node energy constraints, and flow conservation constraints. We conduct extensive computational experiments on the optimization problems and find that the lifetime can be increased significantly as compared to not only the stationary sink model but also more traditional mobile sink models. We also show that the delay tolerance level does not affect the maximum lifetime of the WSN.

Wireless sensor networks with the mobile sink can help to prevent the hot-spot problem and improve the network lifetime. However, in practice, the trajectories of the sink can not ideally change due to the obstacle of the environment or the requirement of the application. The constraint on trajectory of the mobile sink causes the different connection time between the mobile sink and the sensor node, which might result in the imbalance depletion of energy. We propose here an efficient data gathering policy to jointly consider the constrained mobility of the sink and the different connection time at the sensor node. The policy increases the network lifetime in wireless sensor networks with path-constrained mobile sink by optimizing the assignment sensor node. In addition, we also propose the policy to cope with the overlapped connection time of the sink and sensor node due to the movement of the sink. The simulation results demonstrate the effectiveness of the proposed policy: by carefully considering the trajectory of the sink and effectively assigning the sensor node, the network lifetime is increased.

Maximization of lifetime of wireless sensor network (WSN) is an emerging area of research in present scenario. Many authors are performing their research work, so that they could achieve lower energy consumption for the sensor network which leads to increase in lifetime of network. Our work focuses on sink mobility in a fixed trajectory within a wireless sensor network while sensed data are required to be collected. We divide the whole sensor network into two different regions as direct communication area (DCA) and multi-hop communication area (MCA). Sensors node that lies in DCA is at one hop count distance from the sink node trajectory while sensors within MCA are at more than one hop count from the trajectory. We considered all the sensors that are within DCA as subsink nodes. During sink mobility, whenever a subsink is closer to the mobile sink node, then it starts transmitting its data to the sink node. But those sensors that are within MCA needs to search an appropriate sink node for sending its sensed data to the subsink so that on further stage, that subsink could provide those data to the sink node whenever it is in nearest proximity of that subsink. Basically, a sink node is the ultimate destination for the data while a subsink node acts as a relay node for the nodes that are within MCA. So our work is to find out the appropriate subsink node from a given set of subsinks. For doing so, we used location-aided routing on global positioning system (GPS)-enabled sensors and sink node. Our work is validated through simulation experiments using NS-2.

Wireless sensor networks (WSNs) are formed using a cluster of sensor nodes (SNs), deployed randomly to perform sensing operations in an area under observation. Due to the unavailability of an external power source, the energy efficiency considered as one of the critical issues in WSNs. Selection of a sensor node (SN) from a wireless sensor network (WSN) cluster to serve as an aggregator or cluster head (CH), considered as an efficient method to increase the lifetime of wireless sensor network (WSN). In this paper, we have proposed an energy efficient CH selection scheme for WSN, to enhance the lifetime and average residual energy of a single WSN cluster. The proposed strategy nominates a group SNs as CHs, based on their channel condition with the base station (BS) and their residual energy. The proposed algorithm is helpful in solving the problem of unbalanced energy consumption in WSNs. Furthermore, the mechanism of using mobile sink during the hand-off stage helps to overcome the delay in data transmission. Moreover, the incorporation of energy harvesting significantly increases the lifetime of WSN. In comparison to a state-of-art technique available in the literature, our scheme shows a 33% increase in lifetime and presents a steady decrease in residual energy for the same rounds of data transmission.

Using the mobile sink for data collection from all sensors is the most highly effective way to prolong the network lifetime of wireless sensor networks(WSNs). Many studies focused on the anchors selection, aiming to reduce the path length of mobile sink and prolong the network lifetime. However, the appropriateness and the number of the selected anchors, which significantly impact the network lifetime of the entire WSNs, still can be improved. This paper proposes a Dynamic Anchor Points Mechanism for data collection, called DAM, aiming to select appropriate anchors under the path length constraint for prolonging the network lifetime. The experimental results show that the proposed DAM outperforms existing data collection mechanisms in term of network lifetime and fairness index.

Mobile sink has been a significant means to prolong the lifetime of Wireless Multimedia Sensor Networks (WMSNs). However, the mobility of the sink makes the modeling of the WMSNs lifetime a more complex issue. Considering the new properties introduced by a mobile sink, this paper proposed a novel model to define the lifetime of WMSNs with a mobile sink based on energy by taking into account the heterogeneity, network delay, delay jitter, data rate, and data accuracy. Tunable coefficients were introduced into the model for the balance of energy consumption and functions in the network. Both theoretical analysis and numerical simulation validate the correctness and effectiveness of the proposed model.

Dissemination of gathered data to sink is one of the main aspects in wireless sensor networks. Gathered data can be sent to the sink either directly or through multi-hop path. For an application like continuous monitoring of data, data have to be reported continuously to sink. As a result, node that form a part of static path towards sink, especially nodes near the sink may dissipate energy rapidly resulting in hotspot problem. Recent studies reveal the use of mobile sink as an efficient method for collecting data, as it avoids the hotspot problem that happens with static sink. While using mobile sink, we need to take care in maintaining dynamic paths and delay constraints. In this paper, we have used the concept of both mobile sink and static sink. Additionally we have introduced a timer and distance based approach for determining a better path. Here, we distribute the load among different CHs and use dynamic shorter paths, as opposed to usual fixed longer paths. Extensive simulations are carried out in Castalia-3.2 for evaluation of our approach. Our results show improved energy efficiency and network lifetime as compared to using static sink and mobile sink separately. The proposed system also reduces end to end delay by which applications like continuous monitoring can be enhanced.

Extensive research is being done on Wireless sensor Networks (WSNs) in present decade. WSNs consist of large number of sensor nodes which perform sensing of certain phenomena and send the sensed data to the sinks. This operation consumes energy of sensor nodes which effects the lifetime of a network. To prolong the lifetime of WSNs various strategies and routing algorithms have been proposed. Use of mobile sinks has proved effective in this respect. In this paper we are analyzing the impact of multiple mobile sinks with proactive hierarchical clustering protocols LEACH and network reactive hierarchical protocol TEEN. This paper will give simulation based analysis of using multiple mobile sinks in network and their effect on lifetime of a network. Performance analysis will be done on basis of dead nodes, alive nodes, throughput and residual energy.

In this paper we investigate the benefits of a heterogeneous architecture for wireless sensor networks composed of a few resource rich mobile nodes and a large number of simple static nodes. These mobile nodes can either act as mobile relays or mobile sinks. To investigate the performance of these two options and the trade-offs associated with these two options, we first consider a finite network. We then compute the lifetime for different routing algorithms for three cases (i) when the network is all static (ii) when there is one mobile sink and (iii) when there is one mobile relay. We find that using the mobile node as a sink results in the maximum improvement in lifetime. We contend however that in hostile terrains, it might not always be possible for the sink to be mobile. We then investigate the performance of a large dense network with one mobile relay and show that the improvement in network lifetime over an all static network is upper bounded by a factor of four. Also, the proof implies that the mobile relay needs to stay only within a two hop radius of the sink. We then construct a joint mobility and routing algorithm which comes close to the upper bound. However this algorithm requires all the nodes in the network to be aware of the location of the mobile node. We then proposed an alternative algorithm, which achieves the same performance, but requires only a limited number of nodes in the network to be aware of the location of the mobile. We finally compare the performance of the mobile relay and mobile sink and show that for a densely deployed sensor field of radius R hops, we require O(R) mobile relays to achieve the same performance as the mobile sink.

ODT: Optimal deadline-based trajectory for mobile sinks in WSN: A decision tree and dynamic programming approach

Using a single fixed sink in wireless sensor networks (WSNs) creates the hotspot problem. Recently, the mobile sink technique is considered as a good solution to the hotspot problem. Mobile sinks travel physically in the network to collect data directly from special nodes, such as cluster heads (CHs). Find the optimal path for the mobile sink is of utmost importance in order to achieve energy efficiency. The ant colony optimization (ACO) algorithm has been founded to be a good solution to meet this objective. Whereas the traditional ACO algorithm and its versions do not restrict the spread of ants which consumes a lot of energy and makes the convergence speed slow. In this paper, we propose an Intelligent ACO-based Routing Protocol with multiple mobile sinks support for wireless sensor networks (named IARP). This proposed protocol divides the WSN into clusters where each one is managed by a CH. The CH selection is conceived in such a way to use the minimum control overhead and also avoid the greedy re-clustering process. It considers not only pheromone but also remaining energy and hop count heuristic parameters. As well, the scope of ants search is restricted to save a lot of energy. Additionally, we have conceived a fault-tolerant algorithm to resume the normal functionality of the network after the failure of critical nodes i.e. CHs. The proposed protocol is tested by using simulations. The results show that the proposed IARP can significantly improve the performance of WSNs compared to other benchmark protocols.

The advantages of deploying mobile sinks (MSs) in wireless sensor networks (WSNs) have attracted tremendous attention recently, because mobility of a sink provides an efficient method to improve data gathering performance in WSNs. However, in such kind of WSN, the efficiency of data dissemination is obviously affected by the trajectory of the MS. Therefore, optimal moving schemes of the MS have been studied in many researches. Nevertheless, in many cases, the trajectory of the MS is not able to change ideally as previous studies assumed but depending on the environmental conditions. In this paper, we focus on the efficiency of data gathering in WSN with a MS whose trajectory cannot change ideally and propose a new data diffusion scheme - implementing a new Pre-Diffusion Algorithm (PDA) in a hierarchical WSN aimed at improving data gathering efficiency. This hierarchical WSN is composed of several clusters, and datatransmission is done by higher powered cluster head (CH) node. Our scheme predetermines the cluster area where the MS is going to arrive in most probability in next period of time. MS fulfills data converging in the cluster head (CH)whose distance to the MS may the smallest compared with other CHs when data gathering starts. Thus more data can be collected with less trajectory length of MS. Simulation results show that our proposed scheme improves data gathering efficiency as compared to conventional scheme.

Data collection is one of the most important research topics in WSNs. In literature, many studies have proposed centralized solutions to cope with the data collection problem. However, most of them considered controllable mobile sink which is controlled by an algorithm to determine its speed, path, stop locations as well as the performed task. In fact, the uncontrollable mobile sink can be also applied to collect data from a given set of deployed sensors. A number of studies assumed that the sink is fixed and all sensors transmit their data to the sink. However, it leads to the problems of unbalanced workload and network disconnection. Some other studies scheduled the controllable mobile sink. However, the algorithms developed by adopting the controllable mobile sink cannot be applied to the scenarios where the uncontrollable mobile sink is adopted. The main reason is that the stops and arrival time of the uncontrollable mobile sink are unknown. In addition, the problems including the high hardware cost and energy limitation of the controllable mobile sink are still needed to be overcome. This paper proposes a distributed data collection mechanism, called Distributed Bus-based Data Collection (DBDC) algorithm, which considers the bus as mobile sink aiming to maximize the amount of collected data and the network lifetime of wireless sensor networks. Applying the proposed DBDC, each sensor negotiates with its neighbors based on a bidding procedure such that the sensor that buffers more data can obtain more sharing slots instead of increasing its power level. To prolong the network lifetime, the sensor with higher remaining energy can enlarge its transmission power, aiming to release more sharing slots to cooperatively help the neighbor that buffers more data. Experimental study reveals that the proposed DBDC algorithm outperforms related works in terms of throughput, network lifetime and fairness.

In this paper, a clustering-based energy-efficient routing protocol is designed to overcome the hotspot problem in Wireless Sensor networks (WSNs). We have divided the sensor nodes into several clusters, each cluster having a Cluster Head (CH) or a leader node and also implemented a centroid-based mobile sink. The sink moves to a location called “Energy Dependent Centroid Point” where the CHs need minimal energy to transmit data to the sink. We have defined this “Centroid Point” by an equation where the residual energies of CHs are used as a “weight factor” on a normal centroid equation. We have simulated the proposed algorithm and analyzed the results by varying the values of the energy weight factor in the centroid equation up to certain limits (α = 0, 1, 2, and 3). The simulation results are compared with WSN’s existing routing protocols having a mobile sink and a static sink. The comparison results show that our proposed centroid model with α = 0, where the mobile sink moves independent of the residual energies of CHs gives better performances in terms of network lifetime, energy loss, and total data packet transmission.

Maximizing the lifetime in wireless sensor networks with multiple mobile sinks having nonzero travel times