A scalable multi-sink gradient-based routing protocol for traffic load balancing

Abstract

Wireless sensor networks have been assumed to consist of a single sink and multiple sensor nodes which do not have mobility. In these networks, sensor nodes near the sink dissipate their energy so fast due to their many-toone traffic pattern, and finally they die early. This uneven energy depletion phenomenon known as the hot spot problem becomes more serious as the number of sensor nodes (i.e., their scale) increases. Recently, multi-sink wireless sensor networks have been envisioned to solve the hot spot problem. Gradient routing protocols are known to be appropriate for the networks in that network traffic is evenly distributed to multiple sinks to prolong network lifetime and they are scalable. Each node maintains its gradient representing the direction toward a neighbor node to reach one of the sinks. In particular, existing protocols allow a sensor node to construct its gradient using the cumulative traffic load of a path for load balancing. However, they have a critical drawback that a sensor node cannot efficiently avoid using the path with the most overloaded node. Hence, this paper introduces a new Gradient routing protocol for LOad-BALancing (GLOBAL) with a new gradient model to maximize network lifetime. The proposed gradient model considers both of the cumulative path load and the traffic load of the most overloaded node over the path in calculating each node's gradient value. Therefore, packets are forwarded over the least-loaded path, which avoids the most overloaded node. In addition, it is known that assigning a unique address to each sensor node causes much communication overhead. Since the overhead increases as the network scales, routing protocols using an address to indicate the receiver in forwarding a packet are not scalable. Thus, GLOBAL also includes an addressing-free data forwarding strategy. Through ns-2 simulation, we verify that GLOBAL achieves better performance than the shortest path routing and load-aware gradient routing ones.

RPL-based routing protocols for multi-sink wireless sensor networks

“…The routing protocols presented in [3], [5], [15], [16], [17] construct and maintain a best data forwarding path towards all sinks. This is done assuming an application selects the sink, hence a routing protocol does not select the sink node for a data packet (in general, this is the only difference compared to gradientbased best sink selection category).…”

“…These hotspot nodes tend to deplete the energy faster, which reduces WSN lifetime. Recent studies demonstrate that using multiple sinks inside a WSN can improve the network's performance and lifetime [3], [4], [5]. Depending on the application, data generated by nodes can have different end-to-end packet delivery delay and reliability requirements.…”

Unbalanced Threshold Based Distributed Data Collection Scheme in Multisink Wireless Sensor Networks

“…The sink with the lowest ID 1 is designated as administrator sink and other sinks are designated as member sinks. We assume that an effective multisink routing protocol, such as the dynamic traffic-aware routing protocol [40] or the scalable gradientbased routing protocol [41], is deployed in the network. Each sensor node can transmit its sensed data to the nearest sink in a multihop manner.…”

Evaluation of available bandwidth as a routing metric for delay-sensitive IEEE 802.15.4-based ad-hoc networks

“…The routing protocols presented in [10][11][12][13][14][15] are gradient-based routing protocols for IEEE 802.15.4-based ad-hoc networks. The gradient is the cost of using a node as a relay.…”