GeoSVR: A map-based stateless VANET routing

Compared with traditional routing techniques, geographic routing has been proven to be more suitable for highly mobile environments like Vehicular Ad-Hoc Networks (VANETs) because of enhanced scalability and feasibility. These routings use greedy modes or forwarding paths to forward packets. However, the dynamic nature of vehicular network such as frequently changed topology, vehicles density and radio obstacles, could create local maximum, sparse connectivity and network partitions. We propose GeoSVR, a geographic stateless routing combined with node location and digital map. The proposed GeoSVR scheme enhances forwarding path to solve local maximum and sparse connectivity problem, and the proposed restricted forwarding algorithm overcomes unreliable wireless channel issues. In our study, simulations and real world experiments were conducted to evaluate the efficacy and efficiency of the proposed solution. Our results show GeoSVR can provide higher packet delivery ratio with comparable latency to other geographic routing schemes.     

一种可绕过障碍物的网格路由算法

无线传感器网络研究的一个重点就是如何利用有限的能量来使得该网络能够在更长的时间内有效的工作。所以网络的节能成为最近研究的一个重点,而网络拓扑控制也是研究节能的一个方面,阐述了一种基于蜂窝式结构[1]的拓扑控制算法。在这种蜂窝式结构的基础上,在路由转发的时候加上地理路由协议（GPSR）中的两个算法：贪心传递（Greedy Forwarding）算法和周界传递（Perimeter Forwarding）算法,以此来绕过一个路由空洞或者障碍物,从而达到节省网络能量,延长网络运行时间的目的。     

面向船舶AIS自组织网络的地理位置路由算法

针对船舶自动识别系统（Automatic Identification System,AIS）的自组织网络路由算法设计问题,提出了一种基于优化的贪婪边界无状态路由（Greedy Perimeter Stateless Routing,GPSR）的技术方案。该方案利用AIS时分多址接入协议,为消息报文提供信道接入方法。首先,设计了位置报文的自适应转发策略,使船舶节点根据网络环境自主决策位置报文的转发行为;其次,通过缩小GPSR贪婪转发的选择范围,减少了因节点运动导致的边缘路由失败情况。仿真结果表明,所提方案实现了AIS船舶节点的有效组网。与现有转发策略相比,自适应转发策略降低92.7%的位置报文转发量,并降低了79.6%的时隙冲突率,可有效提高网络资源的利用率。      

Hop count optimal position-based packet routing algorithms for ad hoc wireless networks with a realistic physical Layer

Existing routing and broadcasting protocols for ad hoc networks assume an ideal physical layer model. We apply the log-normal shadow fading model to represent a realistic physical layer and use the probability p(x) for receiving a packet successfully as a function of distance x between two nodes. We define the transmission radius R as the distance at which p(R)=0.5. We propose a medium access control layer protocol, where receiver node acknowledges packet to sender node u times, where u*p(x)/spl ap/1. We derived an approximation for p(x) to reduce computation time. It can be used as the weight in the optimal shortest hop count routing scheme. We then study the optimal packet forwarding distance to minimize the hop count, and show that it is approximately 0.73R (for power attenuation degree 2). A hop count optimal, greedy, localized routing algorithm [referred as ideal hop count routing (IHCR)] for ad hoc wireless networks is then presented. We present another algorithm called expected progress routing with acknowledgment (referred as aEPR) for ad hoc wireless networks. Two variants of aEPR algorithm, namely, aEPR-1 and aEPR-u are also presented. Next, we propose projection progress scheme, and its two variants, 1-Projection and u-Projection. Iterative versions of aEPR and projection progress attempt to improve their performance. We then propose tR-greedy routing scheme, where packet is forwarded to neighbor closest to destination, among neighbors that are within distance tR. All described schemes are implemented, and their performances are evaluated and compared.     

一种环境感知的无线Mesh网络自适应QoS路径选择算法

本文针对如何改善无线多跳Mesh网络的服务质量,满足无线多媒体业务对数据传输的带宽、时延、抖动的要求等问题,研究了一种基于无线信道状态和链路质量统计的MAC层最大重传次数的自适应调整算法。该算法通过对无线Mesh网络的无线信道环境的动态感知,利用分层判断法区分无线分组丢失的主要原因是无线差错还是网络拥塞导致,实时调整MAC层的最佳重传次数,降低无线网络中的分组冲突概率。基于链路状态信息的统计和最大重传策略,提出了一种启发式的基于环境感知的QoS路由优化机制HEAOR。该算法通过动态感知底层链路状态信息,利用灰色关联分析法自适应选择最优路径,在不增加系统复杂度的基础上,减少链路误判概率,提高传输效率。NS2仿真结果表明,HEAOR算法能有效减少重路由次数,降低链路失效概率,提高网络的平均吞吐率。本文提出的方法不仅能够优化MAC层的重传,而且通过发现跨层设计的优化参数实现对路径的优化选择。      

Planar graph routing on geographical clusters

Geographic routing protocols base their forwarding decisions on the location of the current device, its neighbors, and the packets destination. Early proposed heuristic greedy routing algorithms might fail even if there is a path from source to destination. In recent years several recovery strategies have been proposed in order to overcome such greedy routing failures. Planar graph traversal was the first of those strategies that does not require packet duplication and memorizing past routing tasks. This article introduces a novel recovery strategy based on the idea of planar graph traversal but performing routing tasks along geographical clusters instead of individual nodes. The planar graph construction method discovered so far needs one-hop neighbor information only, but may produce disconnection even if there is a path from source to destination. However, simulation results show that the proposed algorithm is a good choice from a practical point of view, since disconnection does only concern sparse networks, while in dense network the proposed algorithm competes with existing solutions and even outperforms planar graph routing methods based on one-hop neighbor information. This paper finally gives an outline of further research directions which show that geographical clusters may be the key to solve some problems that come along with planar graph routing in wireless networks.     

无线传感器网络自适应并发多路由算法

无线传感器网络地理位置路由算法需要克服本地最小化现象.已有的算法均以"右手规则"为基础来克服这一现象,但是,"右手规则"会损失链路且难以在路由过程中动态调整所选路由,对自适应多路由选择不利.通过深入分析本地最小化现象,发现合理限定贪心算法的选路区域可以克服本地最小化现象,由此提出Clockwise Rule,该规则不损失链路,可动态调整所选路由,耗费低.在此基础上,提出了自适应并发多路由算法APMR(Adaptive Parallel Multi-path Routing).算法是分布式的,可在任意中继节点处动态调整路由策略,优化路由过程.仿真结果表明APMR算法对网络性能有很好的改善.     

无线传感器网络路由协议的设计与实现

针对传统路由协议端到端时延长、丢包率过高的现实问题,提出了一种基于贪婪转发的能量感知多路径路由协议(Greedy Forward Energy-aware Multipath Routing Protocol,GFEMRP)。GFEMRP从传感器起始结点出发,如果遇到网络黑洞则选择周边转发方式,否则将选择吞吐量大、且更接近于目的结点的结点作为下一跳结点。利用了OMNET++5.0和INET框架对包括无线自组网按需平面距离向量路由协议(Ad hoc on-demand distance vector routing protocol,AODV),动态按需无线自组织网络(Dynamic MANET On-demand,DYMO),贪婪周边无状态路由无线网络(Greedy Perimeter Stateless Routing for Wireless Networks,GPSR)和GFEMRP协议在内的四种路由协议进行了仿真和比较,实验结果表明GFEMRP协议具有良好的端到端时延、丢包率等性能。     

The Impact of Deployment Pattern and Routing Scheme on the Lifetime in Multi-Sink Wireless Sensor Network

Extensive use of sensor and actuator networks in many real-life applications introduced several new performance metrics at the node and network level. Since wireless sensor nodes have significant battery constraints, therefore, energy efficiency, as well as network lifetime, are among the most significant performance metrics to measure the effectiveness of given network architecture. This work investigates the performance of an event-based data delivery model using a multipath routing scheme for a wireless sensor network with multiple sink nodes. This routing algorithm follows a sink initiated route discovery process with the location information of the source nodes already known to the sink nodes. It also considers communication link costs before making decisions for packet forwarding. Carried out simulation compares the network performance of a wireless sensor network with a single sink, dual sink, and multi sink networking approaches. Based on a series of simulation experiments, the lifetime aware multipath routing approach is found appropriate for increasing the lifetime of sensor nodes significantly when compared to other similar routing schemes. However, energy-efficient packet forwarding is a major concern of this work; other network performance metrics like delay, average packet latency, and packet delivery ratio are also taken into the account.

     

无线自组织网络中一种拥塞意识的多径路由算法

提出了无线自组织网络中一种拥塞意识的多径路由算法。该算法在路由发现过程中,综合节点的队列长度和路径跳数来动态确定路由请求消息的转发概率,可以在保证路由请求消息有一定送达率的条件下,降低路由开销;在路径选择和流量分配过程中,综合考虑节点的队列长度和路径质量作为路由度量,发现流量高吞吐量低拥塞路径,并基于该度量值进行流量分配。仿真结果显示,所提出的多径路由算法能有效提高网络性能。     

Research on optimal intelligent routing algorithm for IoV with machine learning and smart contract

The huge increase in the communication network rate has made the application fields and scenarios for vehicular ad hoc networks more abundant and diversified and proposed more requirements for the efficiency and quality of data transmission. To improve the limited communication distance and poor communication quality of the Internet of Vehicles (IoV), an optimal intelligent routing algorithm is proposed in this paper. Combined multi-weight decision algorithm with the greedy perimeter stateless routing protocol, designed and evaluated standardized function for link stability. Linear additive weighting is used to optimize link stability and distance to improve the packet delivery rate of the IoV. The blockchain system is used as the storage structure for relay data, and the smart contract incentive algorithm based on machine learning is used to encourage relay vehicles to provide more communication bandwidth for data packet transmission. The proposed scheme is simulated and analyzed under different scenarios and different parameters. The experimental results demonstrate that the proposed scheme can effectively reduce the packet loss rate and improve system performance.     

Up-Down Links Dualpath Greedy Routing Protocol for Wireless Sensor Networks

Greedy geographic routing is attractive in wireless sensor networks because of its efficiency and scalability. This paper presents an up-down links dualpath greedy routing (UDLDGR) protocol for wireless sensor networks. The routing protocol not only reserves the features of greedy forwarding algorithm, which is simple, efficient, but also uses different relay nodes to serve as routing nodes for up and down routing paths, makes the energy consumption more balanced. The greatest advantage of UDLDGR is it trades off only small cost for the source node to obtain two different transmission paths information. The multipath strengthens the network reliability, such as load balancing and robustness to failures. Our simulation results show that UDLDGR can improve system lifetime by 20–100% compared to single path approaches.     

基于博弈的协作路由算法

协作虚拟多输入多输出（VMIMO）传输是一种有效的无线传输性能优化技术。将物理层协作VMIMO技术和网络层路由选择技术相结合,设计跨层VMIMO路由选择方案可以利用VMIMO的分集增益,显著地降低网络传输能耗。如何设计VMIMO协作路由协议抵抗无线网络的自私节点和欺骗行为,保证高数据转发率和低传输能耗成为路由设计中的重大挑战。为了提高自私网络的VMIMO路由性能,提出了一种基于重复路由博弈的VMIMO协作路由算法。该算法将网络划分成多个Group、Group间使用VMIMO传输数据。将Group间路由选择过程建模为重复路由博弈过程。为了提高数据转发的成功率,提出适用度函数评估节点参与数据分组转发的信誉。以此为基础,提出基于适用度的路由选择子算法和路由转发子算法。理论证明所提重复路由博弈可达到帕累托最优。仿真实验结果表明本算法可以促进自私节点相互合作,可获得较高的数据转发率,较好地减少数据传输时延以及能量消耗。     

无线传感器网络中一种高能效低延时的泛洪算法研究

提出了一种新的应用于无线传感器网络的泛洪传播算法——覆盖优先泛洪算法。算法采用覆盖优先策略为相邻节点分配不同的转发优先权，实现泛洪包快速覆盖整个网络；采用节点转发抑制策略和动态延时转发机制，尽可能抑制冗余包和减少冲突重传。仿真结果表明，该算法与同类算法相比，具有更高的能源有效性，更低的延时。     

Energy Efficient Location Error Resilient Connectivity in Wireless Sensor Networks

Geographic routing for realistic conditions is often permeated with localization errors resulting in poor performance and high energy consumption. We propose a simple yet novel geographic routing method to accomplish routing in the presence of location and channel errors. In this algorithm, it is proposed that next hop node is selected based on the combined probability of distance, estimated location error and estimated channel access probability associated with neighbor nodes. The metrics observed for performance were the successful packet delivery rate and the energy consumed. Our algorithms performance is better compared to greedy forwarding techniques of algorithms such as Greedy routing scheme (GRS) and geographic random forwarding (GeRaF). Simulations show the throughput for our algorithm is better compared to others along with reducing the energy wasted on lost packets.

     

Mobile backbone synthesis for ad hoc wireless networks

In this paper, we present an extended mobile backbone network topology synthesis algorithm (ETSA) for constructing and maintaining a dynamic backbone structure for mobile ad hoc wireless networks. We present and analyze the mathematical features of the proposed scheme. Using these results, we prove that: (1) The ETSA scheme converges in constant time; (2) The length of each control packet is bounded by a constant value that is independent of the number of network nodes; (3) The size of the backbone network depends only on the size of the operational area and is independent of nodal density. We compare the performance features of this scheme with those characterizing other protocols that employ clustering operations and/or use selective forwarding on demand routing methods. In addition, we present an on-demand routing protocol (MBNR) that makes use of the underlying dynamically self-configuring backbone network infrastructure and demonstrate its performance advantages when compared with an on-demand routing protocol that is based on a flat architecture, as well as with other backbone-based routing protocols.     

An implementation framework for trajectory-based routing in ad hoc networks

Routing in ad hoc networks is a complicated task because of many reasons. The nodes are low-memory, low-powered, and they cannot maintain routing tables large enough for well-known routing protocols. Because of that, greedy forwarding at intermediate nodes is desirable in ad hoc networks. Also, for traffic engineering, multi-path capabilities are important. So, it is desirable to define routes at the source like in source based routing (SBR) while performing greedy forwarding at intermediate nodes.We investigate trajectory-based routing (TBR) which was proposed as a middle-ground between SBR and greedy forwarding techniques. In TBR, source encodes trajectory to be traversed and embeds it into each packet. Upon the arrival of each packet, intermediate nodes decode the trajectory and employ greedy forwarding techniques such that the packet follows its trajectory as much as possible.In this paper, we address various issues regarding implementation of TBR. We also provide techniques to efficiently forward packets along a trajectory defined as a parametric curve. We use the well-known Bezier parametric curve for encoding trajectories into packets at source. Based on this trajectory encoding, we develop and evaluate various greedy forwarding algorithms     

Throughput oriented forwarders selection analysis for opportunistic routing in wireless mesh network

Opportunistic routing explicitly takes advantage of the broadcast nature of wireless communications by using a set of forwarders to opportunistically perform packet forwarding. A key issue in the design of opportunistic routing protocols is the forwarder list selection problem. This paper proposes a novel routing metric which shows the end-to-end throughput and a corresponding throughput oriented opportunistic routing forwarder-selecting algorithm throughput oriented forwarders selection (TOFS) through analyzing forwarding characteristics of forwarders. The algorithm puts forward a constraint mechanism that controls the number of forwarders by constraint of throughput for forwarders selection, achieving a better balance between number of forwarders and effective link stability by introducing the factor of transmission time. Simulation results show that the algorithm can improve the network end-to-end throughput effectively over existing methods.     

Greedy Routing with Anti-Void Traversal for Wireless Sensor Networks

The unreachability problem (i.e., the so-called void problem) that exists in the greedy routing algorithms has been studied for the wireless sensor networks. Some of the current research work cannot fully resolve the void problem, while there exist other schemes that can guarantee the delivery of packets with the excessive consumption of control overheads. In this paper, a greedy anti-void routing (GAR) protocol is proposed to solve the void problem with increased routing efficiency by exploiting the boundary finding technique for the unit disk graph (UDG). The proposed rolling-ball UDG boundary traversal (RUT) is employed to completely guarantee the delivery of packets from the source to the destination node under the UDG network. The boundary map (BM) and the indirect map searching (IMS) scheme are proposed as efficient algorithms for the realization of the RUT technique. Moreover, the hop count reduction (HCR) scheme is utilized as a short-cutting technique to reduce the routing hops by listening to the neighbor's traffic, while the intersection navigation (IN) mechanism is proposed to obtain the best rolling direction for boundary traversal with the adoption of shortest path criterion. In order to maintain the network requirement of the proposed RUT scheme under the non-UDG networks, the partial UDG construction (PUC) mechanism is proposed to transform the non-UDG into UDG setting for a portion of nodes that facilitate boundary traversal. These three schemes are incorporated within the GAR protocol to further enhance the routing performance with reduced communication overhead. The proofs of correctness for the GAR scheme are also given in this paper. Comparing with the existing localized routing algorithms, the simulation results show that the proposed GAR-based protocols can provide better routing efficiency.     

无线多跳网络中一种基于网络编码的机会路由

近年来机会路由和网络编码是两种利用无线信道广播特性提高网络性能的新兴技术。相比传统的静态路由决策,机会路由利用动态和机会路由选择减轻无线有损链路带来的影响。网络编码可以提高网络的资源利用率。但编码机会依赖于多个并发流所选路径的相对结构。为了创造更多的网络编码机会和提高网络吞吐量,本文提出了一种基于流间网络编码的机会路由(ORNC)算法。在ORNC中,每个分组转发的机会路径选择是基于网络编码感知的方式进行的。当没有编码机会时,采用背压策略选择下一跳转发路径以平衡网络负载。仿真结果表明本文提出的ORNC算法能够提高无线多跳网络的吞吐量。