Fucai Yu

Elastic routing: a novel geographic routing for mobile sinks in wireless sensor networks

Geographic routing has been considered as an efficient, simple and scalable routing protocol for wireless sensor networks, since it exploits pure location information instead of global topology information to route data packets towards a static sink. Recently, a number of research works have shown that mobile sinks can achieve high energy efficiency and load balance than static ones. In order to receive data packets continuously, a mobile sink must update its location to the source frequently. However, frequent location updates of mobile sinks may lead to both rapid energy consumption of the sensor nodes and increased collisions in wireless transmissions. The authors propose a novel geographic routing for mobile sinks to address this issue. The proposed scheme takes advantage of wireless broadcast transmission nature of wireless sensor nodes. When a sink moves, the new location information is propagated along the reverse geographic routing path to the source during data delivery. Analysis and simulation results indicate that elastic routing is superior to other protocols in terms of control overhead, data delivery delay and energy consumption.

Efficient Hole Detour Scheme for Geographic Routing in Wireless Sensor Networks

Geographic routing has been addressed in many literatures of ad hoc sensor networks due to its efficiency and scalability. Void areas (holes) bring Geographic routing some problems such as data congestion and excessive energy consumption of hole boundary nodes. Holes are hardly avoided in wireless sensor networks due to various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption, even physical destruction. To bypass a hole, most existing geographic routing protocols tend to route data packets along the boundary of the hole by perimeter routing scheme. This scheme, on one hand, consumes more energy of the nodes on the boundary of the hole, thus possibly enlarging the hole, we call this hole diffusion problem; on the other hand, it may incur data congestion if multiple communication sessions are bypassing the hole simultaneously. In this paper, we propose efficient hole detour scheme to solve the hole problems faced by geographic routing in wireless sensor networks. Simulation results show that the proposed protocol is superior to other protocols in terms of packet deliver ratio, control overhead, average delivery delay, and energy consumption.

Energy-aware geographic routing in wireless sensor networks with anchor nodes

Energy efficiency has become an important design consideration in geographic routing protocols for wireless sensor networks because the sensor nodes are energy constrained and battery recharging is usually not feasible. However, numerous existing energy-aware geographic routing protocols are energy-inefficient when the detouring mode is involved in the routing. Furthermore, most of them rarely or at most implicitly take into account the energy efficiency in the advance. In this paper, we present a novel energy-aware geographic routing (EAGR) protocol that attempts to minimize the energy consumption for end-to-end data delivery. EAGR adaptively uses an existing geographic routing protocol to find an anchor list based on the projection distance of nodes for guiding packet forwarding. Each node holding the message utilizes geographic information, the characteristics of energy consumption, and the metric of advanced energy cost to make forwarding decisions, and dynamically adjusts its transmission power to just reach the selected node. Simulation results demonstrate that our scheme exhibits higher energy efficiency, smaller end-to-end delay, and better packet delivery ratio compared to other geographic routing protocols. Copyright

Energy-Efficient Data Dissemination Protocol for Detouring Routing Holes in Wireless Sensor Networks

Void areas (holes) as an inevitable phenomenon exist in geographic routing of wireless sensor networks, because the unpredictable and harsh nature application environment or uneven energy consumption. Most of the existing schemes for the issue tend to construct a static detour path to bypass a hole. The static detour path may lead to uneven energy consumption of the nodes on the perimeter of the hole; thus it may enlarge the hole. At the same time, traffic would concentrate on the peripheral node of the hole; thus the nodes on the perimeter of the hole tend to be depleted quickly. In previous work, we have proposed a hole geometric model to reduce the energy consumption and packet collisions of the nodes on the hole boundary. This scheme, however, still has the static detour path problem. Therefore, we extend the previous work by constructing a dynamic detour path hole geometric model for wireless sensor networks in this paper. The location of hole detour anchor is dynamically shifted according to Gaussian function, just generating dynamic hole detour paths.

Sink Location Service for Geographic Routing in Wireless Sensor Networks

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of the sinks. How can source nodes get sinks locations with low overhead is a difficult issue in wireless sensor networks. In this paper, we propose a Sink Location Service for geographic routing in wireless Sensor Networks. In this scheme, a source node and a sink node send sink location announcement and query messages along two paths respectively by geographic routing. The node located on the crossing point of the two paths informs the source about the sink location. Then the source can send data packet to the sink by geographic routing. How to guarantee that these two paths have at least one crossing point in any irregular profile of sensor network is the challenge of this paper. Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.

Data gathering mechanism with local sink in geographic routing for wireless sensor networks

Most existing geographic routing protocols on sensor networks concentrates on finding ways to guarantee data forwarding from the source to the destination, and not many protocols have been done on gathering and aggregating data of sources in a local and adjacent region. However, data generated from the sources in the region are often redundant and highly correlated. Accordingly, gathering and aggregating data from the region in the sensor networks is important and necessary to save the energy and wireless resources of sensor nodes. We introduce the concept of a local sink to address this issue in geographic routing. The local sink is a sensor node in the region, in which the sensor node is temporarily selected by a global sink for gathering and aggregating data from sources in the region and delivering the aggregated data to the global sink. We next design a Single Local Sink Model for determining optimal location of single local sink. Because the buffer size of a local sink is limited and the deadline of data is constrained, single local sink is capable of carrying out many sources in a large-scale local and adjacent region. Hence, we also extend the Single Local Sink Model to a Multiple Local Sinks Model. We next propose a data gathering mechanism that gathers data in the region through the local sink and delivers the aggregated data to the global sink. Simulation results show that the proposed mechanism is more efficient in terms of the energy consumption, the data delivery ratio, and the deadline miss ratio than the existing mechanisms.

A Communication Architecture to Reflect User Mobility Issue in Wireless Sensor Fields

Typical sensor networks consist of users, sinks, and a number of sensor nodes. The traditional architecture usually assumes that there is a legacy network between users and sinks. However, practical users like firefighters and soldiers move around sensor fields and they might not have any direct communication through legacy networks. In other words, sensor networks are the only communication channel between users and sinks in practical sensor fields. Now there are no researches with respect to architecture to support the user mobility. Thus it is necessary to deliberate a new architecture for such the issue. In this paper, a novel communication architecture was presented where a user operates around an infrastructureless sensor field. A new networking model was then proposed, named dynamic sink model, to support user mobility on the novel architecture. In the model a sink is temporarily selected among generic sensor nodes by a user when the user wants to get information from a sensor network. The chosen sink gathers data from sensor nodes for interested tasks and propagates collected information to the user via the sensor network. The performance of the dynamic sink model on the novel architecture was evaluated and explored with regard to average delay, delivery ratio, and network lifetime compared with the common static sink network model on typical communication architecture.

Communication model and protocol based on multiple static sinks for supporting mobile users in wireless sensor networks

Typical communication model of wireless sensor networks consists of users, sinks, and a number of sensor nodes. The users are remote from wireless sensor networks and they gather data from the sinks via legacy networks. However, in practical sensor network applications, there are two types of users: traditional remote users and mobile users such as fire-fighters and soldiers. The mobile users may move around sensor fields and they communicate with the sinks only via the sensor networks in order to gather data like location information of victims in disaster areas. In this paper, in order to effectively support both the remote users and the mobile users, we propose a novel communication model relying on the typical sensor network model. In the model, multiple static sinks connect with legacy networks and divide a sensor field into the number of the multiple sinks. Through sharing queries and data via the legacy networks, the multiple static sinks provide high throughput through distributed data gathering and low latency through short-hops data delivery. Multiple static sinks deliver the aggregated data to the remote users via the legacy networks. In case of the mobile users, when a mobile user moves around, it receives the aggregated data from the nearest static sink. Simulation results show that the proposed model is more efficient in terms of energy consumption, data delivery ratio, and delay than the existing models.

Energy-aware interference-sensitive geographic routing in wireless sensor networks

Energy conservation and interference reduction are the two ultimate goals in the design of network protocols for wireless sensor networks (WSNs). Energy-aware geographic routing has been considered as an attractive routing scheme for energy conservation in WSNs owing to its desirable scalability and simplicity. However, most energy-aware geographic routing protocols seldom consider interference reduction. The authors present an energy-aware interference-sensitive geographic routing (EIGR) protocol, which focuses on minimising the total network energy consumption and reducing interference. EIGR adaptively uses an anchor list to guide data delivery, and selects the minimum-interference link from energy-optimal relay region for data delivery. To further reduce the energy consumption and interference, EIGR adjusts the transmission power of each forwarding node so as just to reach the selected next forwarding node. Simulation results demonstrate that the proposed approach exhibits noticeably higher energy efficiency, shorter end-to-end delay and higher packet delivery ratio compared with other geographic routing protocols.

Energy-aware multipath geographic routing for detouring mode in wireless sensor networks

For energy-constrained wireless sensor networks, we present an Energy-aware Multipath Geographic Routing (EMGR) protocol. EMGR utilizes geographic information, the characteristics of energy consumption and the metric of advanced energy cost to select the next forwarding node, and uses a dynamic anchor list to shift routing path for load balance. Simulation results show that EMGR is superior to other protocols in terms of energy efficiency, network lifetime, end-to-end delay, and packet delivery ratio. Copyright