Geo-routing Algorithms Research Articles

A Generic Data-Driven Recommendation System for Large-Scale Regular and Ride-Hailing Taxi Services

Modern taxi services are usually classified into two major categories: traditional taxicabs and ride-hailing services. For both services, it is required to design highly efficient recommendation systems to satisfy passengers’ quality of experience and drivers’ benefits. Customers desire to minimize their waiting time before rides, while drivers aim to speed up their customer hunting. In this paper, we propose to leverage taxi service efficiency by designing a generic and smart recommendation system that exploits the benefits of Vehicular Social Networks (VSNs). Aiming at optimizing three key performance metrics, number of pick-ups, customer waiting time, and vacant traveled distance for both taxi services, the proposed recommendation system starts by efficiently estimating the future customer demands in different clusters of the area of interest. Then, it proposes an optimal taxi-to-region matching according to the location of each taxi and the future requested demand of each region. Finally, an optimized geo-routing algorithm is developed to minimize the navigation time spent by drivers. Our simulation model is applied to the borough of Manhattan and is validated with realistic data. Selected results show that significant performance gains are achieved thanks to the additional cooperation among taxi drivers enabled by VSN, as compared to traditional cases.

Geo-Routing Algorithms and Protocols for Power Line Communications in Smart Grids

Making electric power grids smart is invariably linked to the implementation of an advanced communication infrastructure that is able to transport sensing, control and automation information timely, reliably and efficiently. Reusing the power line themselves to realize (part of) this infrastructure is an obvious choice that has a long and successful track record with power utilities. In this paper, we propose to make use of the fact that the nodes of a power line communications (PLCs) network are stationary to deliver messages fast and energy efficiently through routes consisting of a series of communication links. In particular, we exploit location information of PLC nodes to route a message along a favorable path. Such geographic or geo-routing is particularly apt for PLC networks with time-varying link qualities, where optimal routes will change with time. We present routing algorithms and protocols for unicast, broadcast, and multicast transmission that use network topology knowledge to determine the message path taking energy and delay constraints into account. We focus on the distribution domain of the power grid and propose decentralized solutions that use of information about the communication neighborhood of a node, which is acquired through proper signaling in the grid.

Trap Array: A Unified Model for Scalability Evaluation of Geometric Routing

Scalable routing for large-scale wireless networks needs to find near shortest paths with low state on each node, preferably sublinear with the network size. Two approaches are considered promising toward this goal: compact routing and geometric routing (geo-routing). To date, the two lines of research have been largely independent, perhaps because of the distinct principles they follow. In particular, it remains unclear how they compare to each other in the worst case, despite extensive experimental results showing the superiority of one or another in particular cases. We develop a novel Trap Array topology model that provides a unified framework to uncover the limiting behavior of 10 representative geo-routing algorithms. We present a series of new theoretical results, in comparison to the performance of compact routing as a baseline. In light of their pros and cons, we further design a Compact Geometric Routing (CGR) algorithm that attempts to leverage the benefits of both approaches. Theoretical analysis and simulations show the advantages of the topology model and the algorithm.

Vehicle to Vehicle GeoNetworking using Wireless Sensor Networks

Vehicular communications will be the next quality step in the development of automotive technologies. Defining these communications is currently in the final step of development, the focus being on standardization and field tests of network devices and Advanced Driver Assistance Systems. However, some issues regarding vehicular communications that require a specific research effort are still open and represent a challenge if the technology is to be ultimately implemented and marketed. One of these challenges is to develop effective GeoNetworking in vehicular communications. This concept means that the Vehicle Ad-hoc NETwork (VANET) data package transmission is organized according to the topographical location of the different network nodes (vehicles), with the data flow being organized optimally so as to cover the surroundings of each vehicle. The core of this GeoNetworking system is the GeoRouting algorithm that supports the optimal routing of the data packages and reorganizes the network structure in accordance with the positions of the nodes. In this paper we present a novel GeoRouting algorithm for unicast communications, based on the evolution of the previous results of vehicular mesh networks using IEEE 802.15.4 Wireless Sensor Networks (WSN) technology. This algorithm has been designed, implemented and validated under controlled conditions and tested in real vehicles on real roads with free-flow traffic. The results suggest that the features of this routing algorithm can be inserted into any vehicular architecture to provide functioning GeoNetworking that will support a wide range of Advanced Driving Assistance System (ADAS) applications.

Trap array

Scalable routing for large-scale wireless networks needs to find near shortest paths with low state on each node, preferably sub-linear with the network size. Two approaches are considered promising toward this goal: compact routing and geometric routing (geo-routing). To date the two lines of research have been largely independent, perhaps because of the distinct principles they follow. In particular, it remains unclear how they compare with each other in the worst case, despite extensive experimental results showing the superiority of one or another in particular cases. We develop a novel Trap Array topology model that provides a unified framework to uncover the limiting behavior of ten representative geo-routing algorithms. We present a series of new theoretical results, in comparison with the performance of compact routing as a baseline. In light of their pros and cons, we further design a Compact Geometric Routing (CGR) algorithm that attempts to leverage the benefits of both approaches. Theoretic analysis and simulations show the advantages of the topology model and the algorithm.

모바일 애드혹 네트워크에서 자가 적응형 위치 검증 기법

위치 기반 라우팅 기법에서는 경로 유지를 위해 모바일 노드 정보를 습득해야 하며 이를 위해 고정된 주기로 비콘 메시지를 자신의 이웃노드에 전송하는 방법이 널리 사용된다. 하지만 비콘 주기가 길어질 경우 모바일 환경에서 이웃 노드 위치 에러 발생 확률이 높아지게 되고, 반면에 짧을 경우 네트워크 내에서 경로 유지를 위한 오버헤드가 커지는 문제가 있다. 이를 위해 비콘 전송 주기를 동적으로 변화시키는 방법이 제안되었으나 최적의 전송 주기를 찾는 것은 동적인 모바일 환경에서 아주 어려운 일이다. 따라서, 부적절한 비콘 전송 주기로 인해 포워딩 테이블 내에서 잘못된 이웃 노드 정보를 유지하는 불확실성 문제가 빈번하게 발생하게 되고 이로 인해 경로 신뢰성과 네트워크 전송률이 낮아지게 된다. 본 논문에서는 이러한 불확실성 문제를 극복하기 위해서 모바일 노드가 스스로 자신의 위치를 체크하는 능동적 포워딩 테이블 갱신기법을 가정하여 자가 적응형 위치 검증 기법을 제안한다. ns2를 이용한 시뮬레이션 결과는 다양한 모바일 환경에서 제안 기법이 기존 방법 보다 라우팅 오버헤드를 줄이면서 경로 신뢰성, 단대 단 전송률이 향상됨을 보여준다. In geographic forwarding algorithms, traditional route maintenance requires mobile nodes periodically exchange beacon messages with their neighbors. In beacon message based forwarding scheme, a longer interval reduces the number of beacons needed, but may result in significant location errors. Conversely, a shorter interval guarantees more accurate location information, but induces control overheads.Therefore, the fixed or dynamic interval scheme based forwarding schemes cannot adapt well to different mobility environments. Also, existing schemes result in the uncertainty of neighbor node's position in the forwarding table of mobile node. Therefore, this paper presents a self-adaptive location checking mechanism based proactive geo-routing algorithm for beacon-based geographic routing. Simulation results show that the proposed routing algorithm not only significantly increases the relay transmission rate but also guarantees the high end-to-end packet delivery in low and high mobility environments.

Message-Efficient Beaconless Georouting With Guaranteed Delivery in Wireless Sensor, Ad Hoc, and Actuator Networks

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Beaconless georouting algorithms are fully reactive and work without prior knowledge of their neighbors. However, existing approaches can either not guarantee delivery or they require the exchange of complete neighborhood information. We describe two general methods for completely reactive face routing with guaranteed delivery. The Beaconless Forwarder Planarization (BFP) scheme determines correct edges of a local planar subgraph without hearing from all neighbors. Face routing then continues properly. Angular Relaying determines directly the next hop of a face traversal. Both schemes are based on the Select-and-Protest principle. Neighbors respond according to a delay function, but only if they do not violate a planar subgraph condition. Protest messages are used to remove falsely selected neighbors that are not in the planar subgraph. We show that a correct beaconless planar subgraph construction is not possible without protests. We also show the impact of the chosen planar subgraph on the message complexity. With the new Circlunar Neighborhood Graph (CNG) we can bound the worst case message complexity of BFP, which is not possible when using the Gabriel graph (GG) for planarization. Simulation results show similar message complexities in the average case when using CNG and GG. Angular Relaying uses a delay function that is based on the angular distance to the previous hop. We develop a theoretical framework for delay functions and show both theoretically and in simulations that with a function of angle and distance we can reduce the number of protests by a factor of 2 compared to a simple angle-based delay function. </para>

A Distributed Geo-Routing Algorithm for Wireless Sensor Networks

Geographic wireless sensor networks use position information for greedy routing. Greedy routing works well in dense networks, whereas in sparse networks it may fail and require a recovery algorithm. Recovery algorithms help the packet to get out of the communication void. However, these algorithms are generally costly for resource constrained position-based wireless sensor networks (WSNs). In this paper, we propose a void avoidance algorithm (VAA), a novel idea based on upgrading virtual distance. VAA allows wireless sensor nodes to remove all stuck nodes by transforming the routing graph and forwarding packets using only greedy routing. In VAA, the stuck node upgrades distance unless it finds a next hop node that is closer to the destination than it is. VAA guarantees packet delivery if there is a topologically valid path. Further, it is completely distributed, immediately responds to node failure or topology changes and does not require planarization of the network. NS-2 is used to evaluate the performance and correctness of VAA and we compare its performance to other protocols. Simulations show our proposed algorithm consumes less energy, has an efficient path and substantially less control overheads.