Equal-cost multi-path routing

About: Equal-cost multi-path routing is a research topic. Over the lifetime, 10472 publications have been published within this topic receiving 249362 citations.

Cross-Layer Aided Energy-Efficient Opportunistic Routing in Ad Hoc Networks

Abstract: Most of the nodes in ad hoc networks rely on batteries, which requires energy saving. Hence, numerous energy-efficient routing algorithms have been proposed for solving this problem. In this paper, we exploit the benefits of cross-layer information exchange, such as the knowledge of the Frame Error Rate (FER) in the physical layer, the maximum number of retransmissions in the Medium Access Control (MAC) layer and the number of relays in the network layer. Energy-consumption-based Objective Functions (OF) are invoked for calculating the end-to-end energy consumption of each potentially available route for both Traditional Routing (TR) and for our novel Opportunistic Routing (OR), respectively. We also improve the TR and the OR with the aid of efficient Power Allocation (PA) for further reducing the energy consumption. For the TR, we take into account the dependencies amongst the links of a multi-hop route, which facilitates a more accurate performance evaluation than upon assuming the links that are independent. Moreover, two energy-efficient routing algorithms are designed based on Dijkstra's algorithm. The algorithms based on the energy OF provide the theoretical bounds, which are shown to be close to the bound found from exhaustive search, despite the significantly reduced complexity of the former. Finally, the end-to-end throughput and the end-to-end delay of this system are analyzed theoretically and a new technique of characterizing the delay distribution of OR is proposed. The simulation results show that our energy-efficient OR outperforms the TR and that their theoretical analysis accurately matches the simulation results.

GLOBAL: A Gradient-based routing protocol for load-balancing in large-scale wireless sensor networks with multiple sinks

Abstract: Recently, multi-sink wireless sensor networks (WSNs) are envisioned to solve the hot spot problem caused by traditional single-sink WSNs. Routing protocols should be able to distribute network traffic evenly to multiple sinks to prolong network lifetime and they should be scalable. Gradient-based routing protocols are known to be suitable for the networks, where each node maintains its gradient representing the direction toward a neighbor node to reach a sink. 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-based routing protocol for load-balancing (GLOBAL) with a new gradient model to maximize network lifetime. In GLOBAL, the least-loaded path which also avoids the most overloaded sensor node is selected for forwarding. Through ns-2 simulation, we verify that GLOBAL achieves better performance than the shortest path routing protocol and load-aware gradient-based routing one.

Power-aware single- and multipath geographic routing in sensor networks

Abstract: Nodes in a sensor network, operating on power limited batteries, must save power to minimize the need for battery replacement. We note that the range of transmission has a significant effect on the power consumption of both the transmitting node and listeners. This paper first presents a Geographical Power Efficient Routing (GPER) protocol for sensor networks. Each sensor node makes local decisions as to how far to transmit: therefore, the protocol is power efficient, localized, highly distributed, and scalable. In GPER, given a final destination, each node first establishes a subdestination within its maximum radio range. The node, however, may decide to relay the packet to this subdestination through an intermediary node or alter the subdestination if this will preserve power. Traditional deterministic geographic routing algorithms aim at achieving close to the shortest weighted paths. However, they normally stick to the same paths for the same source/destination pairs. This may conversely drain the nodes on these paths and result in short network life when the communication in the network is unevenly distributed. Thus, we further investigate a set of probabilistic multipath routing algorithms, which generate braided multipaths based only on local information. The algorithms have less communication and storage overhead than conventional on-demand multipath routing algorithms, while providing greater resilience to node failures. Simulations on NS2 show that GPER almost halves the power consumption in the network relative to alternative geographic routing algorithms. Furthermore, in situations where the communication tasks are non-uniformly distributed, probabilistic multipath routing contributes up to an additional 30% to network lifetime.

Multilevel global placement with congestion control

Abstract: In this paper, we develop a multilevel global placement algorithm (MGP) integrated with fast incremental global routing for directly updating and optimizing congestion cost during physical hierarchy generation. Fast global routing is achieved using a fast two-bend routing and incremental A-tree algorithm. The routing congestion is modeled by the wire usage estimated by the fast global router. A hierarchical area density control is developed for placing objects with significant size variations. Experimental results show that, compared to GORDIAN-L, the wire length-driven MGP is 4-6.7 times faster and generates slightly better wire length for test circuits larger than 100000 cells. Moreover, the congestion-driven MGP improves wiring overflow by 45%-74% with 5% larger bounding box wire length but 3%-7% shorter routing wire length measured by a graph-based A-tree global router.

Aligned Virtual Coordinates for Greedy Routing in WSNs

Abstract: Geographic routing protocols achieve relatively good performance, and provide several advantages over conventional protocols for multihop wireless networks. However, such protocols are impacted by physical voids, and localization errors. Virtual coordinate systems (VCS) were proposed as an alternative approach that is resilient to localization errors and that naturally routes around physical voids. In this paper, we show that VCS is vulnerable to different forms of the void problem and, in general, perform worse than geographic routing in the greedy phase. We show that these anomalies arise from quantization noise in the estimate of connectivity and node location due to the integral nature of VCS co-ordinates. We propose an aligned virtual coordinate system (AVCS) on which the greedy routing success can be significantly improved. With our approach, and for the first time, we show that greedy routing on VCS outperforms that on geographic coordinates even with no localization errors. We compare AVCS against some of the most popular geometric routing protocols both using physical and virtual coordinates and show that it significantly improves performance over these solutions.