Arshad Sher

Network lifetime maximization via energy hole alleviation in wireless sensor networks

Energy hole creation is one of the most important issues in Wireless Sensor Networks (WSNs). This paper aims to analyze the energy hole boundary for avoiding the creation of energy hole such that network lifetime is prolonged. An analytical model is presented to analyze the network lifetime and location of energy hole from the start of network till the death of last node. Also network area is logically divided to minimize data loss.

Monitoring square and circular fields with sensors using energy-efficient cluster-based routing for underwater wireless sensor networks:

In this article, to monitor the fields with square and circular geometries, three energy-efficient routing protocols are proposed for underwater wireless sensor networks. First one is sparsity-aware energy-efficient clustering, second one is circular sparsity-aware energy-efficient clustering, and the third one is circular depth–based sparsity-aware energy-efficient clustering routing protocol. All three protocols are proposed to minimize the energy consumption of sparse regions, whereas sparsity search algorithm is proposed to find sparse regions and density search algorithm is used to find dense regions of the network field. Moreover, clustering is performed in dense regions to minimize redundant transmissions of a data packet, while sink mobility is exploited to collect data from sensor nodes with an objective of minimum energy consumption. A depth threshold ( d th ) value is also used to minimize number of hops between source and destination for less energy consumption. Simulation results show that our schemes perform better than their counter-part schemes (depth-based routing and energy-efficient depth-based routing) in terms of energy efficiency.

Position adjustment-based location error-resilient geo-opportunistic routing for void hole avoidance in underwater sensor networks: Geo-opportunistic routing for void hole avoidance in underwater WSNs

This paper presents four routing protocols for Underwater Sensor Networks (USNs): Location Error–resilient Transmission Range adjustment–based protocol (LETR), Mobile Sink–based GEographic and Opportunistic Routing (MSGER), Mobile Sink–based LETR (MSLETR), and Modified MSLETR (MMS‐LETR). LETR considers transmission range levels for finding neighbor nodes. If a node fails to find any neighbor node within its defined maximum transmission range level, it recovers from communication void regions using depth adjustment technology. MSGER and MSLETR avoid depth and transmission range adjustment and overcome the problem of communication void regions using MSs, whereas MMS‐LETR takes into account noise attenuation at various depth levels, elimination of retransmissions using multi‐path communication and load balancing. The performance of our proposed protocols is evaluated through simulations using different parameters. The simulation results show that MSS‐LETR supersedes all counterpart schemes in terms of packet loss ratio. LETR significantly improves network performance in terms of energy consumption, packet loss ratio, fraction of void nodes, and the total amount of depth adjustment.

Retransmission Avoidance for Reliable Data Delivery in Underwater WSNs

The energy-efficient and reliable delivery of data packets in resource constraint underwater wireless sensor networks (UWSNs) is one of the key considerations to enhance the network lifetime. The traditional re-transmissions approach consumes the node battery and increases the communication overhead, which results in congestion and affects the reliable data packet delivery in the network. To ensure the reliability and conserve the node battery, in this paper, we propose adaptive forwarding layer multipath power control routing protocol to reduce the energy dissipation, achieve the data reliability and avoid the energy hole problem. In order to achieve the reliability, tree based topology is exploited to direct multiple copies of the data packet towards the surface through cross nodes in the network. The energy dissipation is reduced by a substantial amount with the selection of low noise path between the source and the destination including the information of neighbors of the potential forwarder node. Extensive simulation results show that our proposed work outperforms the compared existing scheme in terms of energy efficiency and packet received ratio (PRR).

MC: Maximum Coverage Routing Protocol for Underwater Wireless Sensor Networks

Deployment of sensor nodes in underwater wireless sensor networks with a goal of maximum network field coverage is very difficult. Moreover, to access the information from sensor nodes efficiently in aquatic environment is very unpredictable. In our scheme sensor nodes are randomly deployed in the network filed. We have cover the maximum network field through constant mobility of two sinks. Due to consistent movement of mobile sinks every time maximum number of sensor nodes transmit their data packets to the respective mobile sink in their transmission range. Mobility of sinks increases the throughput with balanced energy consumption. Simulation results show that, MC protocol perform better in terms of network lifetime, throughput and energy consumption.

AVN-AHH-VBF: Avoiding Void Node with Adaptive Hop-by-Hop Vector Based Forwarding for Underwater Wireless Sensor Networks

In this paper, we propose a routing protocol AVN-AHH-VBF for underwater wireless sensor networks (UWSNs). Sensor nodes forward data packets in multi-hop fashion within a virtual pipeline. As nodes outside pipeline do not forward data packets, thus, flooding is avoided in the network. Mitigating flooding in network, in turn, decreases energy consumption and improves delivery ratio. Moreover, on each hop, forwarding towards void region of the network is avoided with the help of two hop information. Avoiding void hole on each hop reduces number of transmissions for a data packet, for which route to sink does not exist. Thus, energy wastage by each dropped packet is reduced. In addition, taking the benefit of broadcast nature of the network, best forwarder (non-void) is selected from the transmission range of a node. Best forwarder selection results in increased delivery ratio. Furthermore, we incorporate two new factors in holding time calculation. First, the number of hops a data packet has already traversed along its journey that is started from source node. Second, the number of neighbors of a node which is calculating the holding time, is incorporated. A sensor node with less number of neighbors holds data packet for long duration of time than the node with more neighbors. By doing so, holding time is reduced on each hop throughout the journey of a data packet. Extensive simulations verify that AVN-AHH-VBF minimizes end-to-end delay upto 57% as compared to existing AHH-VBF. Also, in the proposed technique, energy wasted by a dropped packet is about 54% less than counterpart technique. At the same time, compared with AHH-VBF, delivery ratio of AVN-AHH-VBF is approximately 8% improved.

Avoiding Void Holes and Collisions with Reliable and Interference-Aware Routing in Underwater WSNs

Sparse node deployment and dynamic network topology in underwater wireless sensor networks (UWSNs) result in void hole problem. In this paper, we present two interference-aware routing protocols for UWSNs (Intar: interference-aware routing; and Re-Intar: reliable and interference-aware routing). In proposed protocols, we use sender based approach to avoid the void hole. The beauty of the proposed schemes is that they not only avoid void hole but also reduce the probability of collision. The proposed Re-Intar also uses one-hop backward transmission at the source node to further improve the packet delivery ratio of the network. Simulation results verify the effectiveness of the proposed schemes in terms of end-to-end delay, packet delivery ratio and energy consumption.

Void Hole Avoidance for Reliable Data Delivery in IoT Enabled Underwater Wireless Sensor Networks

Due to the limited availability of battery power of the acoustic node, an efficient utilization is desired. Additionally, the aquatic environment is harsh; therefore, the battery cannot be replaced, which leaves the network prone to sudden failures. Thus, an efficient node battery dissipation is required to prolong the network lifespan and optimize the available resources. In this paper, we propose four schemes: Adaptive transmission range in WDFAD-Depth-Based Routing (DBR) (A-DBR), Cluster-based WDFAD-DBR (C-DBR), Backward transmission-based WDFAD-DBR (B-DBR) and Collision Avoidance-based WDFAD-DBR (CA-DBR) for Internet of Things-enabled Underwater Wireless Sensor Networks (IoT, UWSNs). A-DBR adaptively adjusts its transmission range to avoid the void node for forwarding data packets at the sink, while C-DBR minimizes end-to-end delay along with energy consumption by making small clusters of nodes gather data. In continuous transmission range adjustment, energy consumption increases exponentially; thus, in B-DBR, a fall back recovery mechanism is used to find an alternative route to deliver the data packet at the destination node with minimal energy dissipation; whereas, CA-DBR uses a fall back mechanism along with the selection of the potential node that has the minimum number of neighbors to minimize collision on the acoustic channel. Simulation results show that our schemes outperform the baseline solution in terms of average packet delivery ratio, energy tax, end-to-end delay and accumulated propagation distance.

Location error resilient geo-opportunistic routing for void hole avoidance in USNs

Underwater sensor networks (USNs) are getting popular for the purpose of monitoring and exploration of undersea terrain. However, underwater communication channel characteristics limits data gathering capacity and duration of monitoring. Efficient routing protocols can improve performance of USNs having dynamic topology and localization errors. This paper presents LETR; a geo-opportunistic routing protocol that considers localization errors and communication void regions. LETR considers transmission range levels for finding neighbor nodes. Sensor nodes search for neighbors by adapting different transmission range levels. The performance of our proposed protocol is evaluated against different parameters through simulations. The simulation results show that LETR significantly improves network performance in terms of energy consumption, packet loss ratio, fraction of void nodes and the total amount of depth adjustment performed by

Adaptive Transmission based Geographic and Opportunistic Routing in UWSNs

UWSNs are frequency selective and energy-hungry due to the underwater acoustic communication links. We propose adaptive transmission based geographic and opportunistic routing (ATGOR) for efficient and reliable communication. Opportunistic routing is utilized along with geographic routing to select a set of forwarders from the neighboring nodes instead of a single forwarder. We propose a 3D network model logically divided into small cubes of equal volume with a goal that the sensed data is transmitted by the unit of small cubes.