DTN-Balance: A Forwarding-Capacity and Forwarding-Queue Aware Routing for Self-organizing DTNs

In delay-tolerant networks (DTNs), intermittent network connectivity and lack of global system information pose serious challenges to achieve effective data forwarding. Most state-of-the-art DTN routing algorithms are based on hill-climbing heuristics in order to select the best available next hop to achieve satisfactory network throughput and routing efficiency. An adverse consequence of this approach is that a small subset of good users take on most of the forwarding tasks. This can quickly deplete scarce resources (e.g. storage, battery, etc.) in heavily utilized devices which degrades the network reliability. A system with a significant amount of traffic carried by a small number of users is not robust to denial of service attacks and random failures. To overcome these deficiencies, this paper proposes a new routing algorithm, DTN-Balance, that takes the forwarding capacity and forwarding queue of the relay nodes into account to achieve a better load distribution in the network. For this, we defined a new routing metric called message forwarding utility combining nodal available bandwidth and forwarding workload. Applying small world theory, we impose an upper bound on the end-to-end hop count that results in a sharp increase in routing efficiency. Queued messages in a forwarding node are arranged by DTN-Balance based on message dropping utility metric for a more intelligent decision in the case of a message drop. The performance of our method is compared with that of the existing algorithms by simulations on real DTN traces. The results show that our algorithm provides outstanding forward efficiency at the expense of a small drop in the throughput.

     

PRP: peripheral routing protocol for WSN realistic marginal mobility model

This article proposes a new routing protocol called Peripheral Routing Protocol (PRP) for the scenario where the mobile destination (D) moves at the wireless sensor network (WSN) periphery for gathering data. From a connectivity point of view, when D follows the marginal mobility model (MMM), the WSN becomes a hybrid network: a sparse network, because of the interrupted connectivity between D and the rest of the nodes and a well-connected network, because of the connectivity between all the other nodes of the WSN except D. It will be proven through MATLAB simulations that, for a military application scenario where D’s connectivity to the WSN varies between 10% and 95%, compared with the 100% case, PRP outperforms routing protocols recommended for Mobile Ad-hoc Networks (MANET) in three ways: it maintains an average Packet Delivery Ratio (PDR) over 90%, a below 10% and 5% increase for the Average End to End Delay (AETED) and energy per transmitted packet.     

无线多跳网络中机会路由效率增强研究(英文)

Opportunistic routing(OR) is an effective way to guarantee transmission reliability in wireless multi-hop networks.However,little research focuses on transmission efficiency.Thus,an analytical model based on open queuing network with Markov chains was proposed to evaluate the efficiency.By analyzing two typical ORs,we find duplicate transmission and collision avoidance overhead are the root reasons behind inefficiency.Therefore,a new scheme called dual priority cooperative opportunistic routing(DPCOR) was proposed.In DPCOR,forwarding candidates are configured with dual priority,which enables the network to classify forwarding candidates more effectively so as to reduce the back-off time and obtain more diversity gain.Theoretical analysis and simulation results show DPCOR achieves significant performance improvement with less time overhead compared with traditional routings and typical ORs.     

Noncooperative Dynamic Routing with Bandwidth Constraint in Intermittently Connected Deep Space Information Networks Under Scheduled Contacts

The increasing world-wide demands in deep space scientific missions, such as Lunar, Mars and other Planetary Exploration, along with the rapidly growing advances in space communication technologies have triggered the vision of so called future Deep Space Information Networks (DSINs). The coined DSIN paradigm is envisioned to be an integrated high speed self-organizing hypernetwork consisting of the terrestrial ground-based information networks and the outer space-based entities to provide maximum network capacity. In this paper, we address the challenges of dynamic routing with bandwidth constraint over intermittently connected Deep Space Backbone Layer (DSBL) of DSINs under scheduled contacts. Firstly, we build up hypergraph model to represent DSBL aiming to improve network connectivity. Taking into account the continuous and random changes of selfish traffic along backbone links as well as the selfish forwarding of joint nodes, we propose a noncooperative dynamic routing model with bandwidth constraint, in which routing decision is related to the continuous-time resource usage. Our routing model includes two effective sub-models: stochastic differential game based noncooperative forwarding model with bandwidth constraints and contact schedule model. In addition, we provide a polynomial time algorithm to describe the procedure of our routing model. This algorithm covers three sub-algorithms considering three different cases based on hypergraph model, i.e., internal forwarding, cross-IS forwarding, cross-island forwarding. Theoretical analysis and numerical results demonstrate the effectiveness and feasibility of our routing model.     

Survey on Wireless Sensor Network Applications and Energy Efficient Routing Protocols

Wireless sensor network (WSN) is a group of small power-constrained nodes that sense data and communicate it to the base station (BS). These nodes cover a vast region of interest (ROI) for several purposes according to the application need. The first challenge encountered in WSNs is how to cover the ROI perfectly and send the monitored data to the BS. Although the energy introduced during setup phase and the violation of energy fairness constraint of dynamic routing topologies, they achieve high network performance in terms of coverage and connectivity. In this paper, we categorize the applications of WSN based on different aspects to show the major protocol design issues. Thus, the energy efficiency of the recent proactive routing protocols is studied from different angles. The energy overhead and energy fairness of each protocol were carefully analyzed. The most energy efficient routing protocols for homogeneous proactive networks were studied and compared to highlight the research challenges and existing problems in this area. The results proved that energy overhead and route selection are the most effective aspects of network lifetime and network efficiency.

     

一种面向高速路车联网场景的自适应路由方法

车载自组织网络中节点的高速移动性使得网络拓扑频繁变化,造成路由效率低下.本文提出了一种面向高速路车联网场景的自适应路由方法.本方法采用了贪婪机会转发（GOF）算法,在选择下一跳转发节点时,同时考虑到目的节点的距离计算、节点间的链路状态以及下一跳的有效节点度状况来找出最优转发节点,并提出新的计算连通概率的方法.仿真实验和实际道路场景的测试表明,与相关算法相比在路由稳定性方面表现出较好的效果.     

WSN中最小代价前向协议的研究与改进

对无线传感器网络（WSN）中的最小代价前向协议进行了研究，通过引入随机选择和数据融合功能改进原有协议。用跳数作为代价分析了改进后的协议性能，并进行计算机仿真，结果表明改进后的协议具有更低的网络负荷和更长的生命周期。     

Active routing for ad hoc networks

Ad hoc networks are wireless multihop networks whose highly volatile topology makes the design and operation of a standard routing protocol hard. With an active networking approach, one can define and deploy routing logic at runtime in order to adapt to special circumstances and requirements. We have implemented several active ad hoc routing protocols that configure the forwarding behavior of mobile nodes, allowing data packets to be efficiently routed between any two nodes of the wireless network. Isolating a simple forwarding layer in terms of both implementation and performance enables us to stream delay-sensitive audio data over the ad hoc network. In the control plane, active packets permanently monitor the connectivity and setup, and modify the routing state     

Joint optimization of energy allocation and routing problems in wireless sensor networks

Energy allocation problems and routing problems are both important research issues in the wireless sensor network (WSN) field. The former usually aims at considering how to allocate a certain number of sensor devices in a sensing region to form a WSN so that the objective function value (e.g., the network connectivity or the network lifetime) of the constructed network is optimized. For the message routing problem in WSNs, researchers tend to consider how to find an energy conservable message transmission routing scheme for notifying the supervisor of the WSN when an event occurs. Till now, many solutions have been proposed for the above two categories of optimization problems. However, unifying the above two network optimization problems to maximize the network lifetime, to the best of our knowledge, still lacks related research. This paper considers a joint optimization problem for energy allocation and energy‐aware routing called the joint optimization of energy allocation and routing problem (JOEARP) for a hierarchical cluster‐based WSN. We propose an exact algorithm to provide the optimum solution for the JOEARP. The simulation results show that this solution performed better in prolonging the network lifetime of a WSN in a real situation, compared to other compositions of conventional energy allocation schemes with some known routing algorithms. Copyright © 2009 John Wiley & Sons, Ltd.     

Adaptive energy aware cluster-based routing protocol for wireless sensor networks

Wireless sensor networks (WSNs) have grown excessively due to their various applications and low installation cost. In WSN, the main concern is to reduce energy consumption among nodes while maintaining timely and reliable data forwarding. However, most of the existing energy aware routing protocols incur unbalanced energy consumption, which results in inefficient load balancing and compromised network lifetime. Therefore, the main target of this research paper is to present adaptive energy aware cluster-based routing (AECR) protocol for improving energy conservation and data delivery performance. Our proposed AECR protocol differs from other energy efficient routing schemes in some aspects. Firstly, it generates balance sized clusters based on nodes distribution and avoids random clusters formation. Secondly, it optimizes both intra-cluster and inter-cluster routing paths for improving data delivery performance while balancing data traffic on constructed forwarding routes and at the end, in order to reduce the excessive energy consumption and improving load distribution, the role of Cluster Head (CH) is shifted dynamically among nodes by exploit of network conditions. Simulation results demonstrate that AECR protocol outperforms state of the art in terms of various performance metrics.

     

分布式能量均衡的WSN动态数据转发策略

针对无线传感器网络中存在的能量空洞问题,该文提出一种能量均衡的层次型数据转发策略。根据节点可用能量、节点之间相对位置及不同网络区域簇头能量消耗速率构建非均匀层次化结构。进而,综合考虑节点簇内通信开销和节点关系选取中继转发节点,并在多跳簇间数据转发时执行数据融合进一步降低转发数据量以实现簇间多跳通信的能量有效性。数值结果表明,所提机制可以有效地均衡网络负载,延长网络生命周期,改善网络数据转发性能。     

BRA: A Bidirectional Routing Abstraction for Asymmetric Mobile Ad Hoc Networks

Wireless links are often asymmetric due to heterogeneity in the transmission power of devices, non-uniform environmental noise, and other signal propagation phenomena. Unfortunately, routing protocols for mobile ad hoc networks typically work well only in bidirectional networks. This paper first presents a simulation study quantifying the impact of asymmetric links on network connectivity and routing performance. It then presents a framework called BRA that provides a bidirectional abstraction of the asymmetric network to routing protocols. BRA works by maintaining multi-hop reverse routes for unidirectional links and provides three new abilities: improved connectivity by taking advantage of the unidirectional links, reverse route forwarding of control packets to enable off-the-shelf routing protocols, and detection packet loss on unidirectional links. Extensive simulations of AODV layered on BRA show that packet delivery increases substantially (two-fold in some instances) in asymmetric networks compared to regular AODV, which only routes on bidirectional links.     

Statistical Multipath Queue-Wise Preemption Routing for ZigBee-Based WSN

Nowadays, wireless sensor network (WSN) is an important component in IoT environment, which enables efficient data collection and transmission. Since WSN consists of a large number of sensor nodes, network congestion can easily occur which significantly degrades the performance of entire network. In this paper a novel scheme called SMQP (Statistical Multipath Queue-wise Preemption) routing is proposed to balance the load and avoid the congestion for ZigBee-based WSN. This is achieved by employing statistical path scheduling and queue-wise preemption with multiple paths between any source and destination node. NS2 simulation reveals that the proposed scheme significantly improves the QoS in terms of delivery ratio, end-to-end delay, and packet delivery ratio compared to the representative routing schemes for WSN such as ad hoc on-demand distance vector and ad hoc on-demand multipath distance vector scheme.     

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.     

A path selection based routing protocol for urban vehicular ad hoc network (UVAN) environment

Routing in urban environment is a challenging task due to high mobility of vehicles in the network. Many existing routing protocols only consider density, link connectivity, delay, and shortest path information to send the data to the destination. In this paper, a routing protocol is proposed which uses the urban road network information such as multi-lane and flyover to send the data to the destination with a minimum packet forwarding delay. The next path for data forwarding is selected based on a path value calculated by the Road Side Unit for each path connected to a junction. This protocol uses Ground Vehicle to Ground Vehicle (GV2GV) communication, Flyover Vehicle to Flyover Vehicle (FV2FV) communication, and Flyover Vehicle to Ground Vehicle/Ground Vehicle to Flyover Vehicle (FV2GV/GV2FV) communication to enhance the routing performance. Simulation results show that proposed protocol performs better than P-GEDIR, GyTAR, A-STAR, and GSR routing protocols in terms of end-to-end delay, number of network gaps, and number of hops.     

Capsule network‐based data pruning in wireless sensor networks

The development of the wireless sensor networks (WSN) being deployed among numerous application for its sensing capabilities is increasing at a very fast tread. Its distributed nature and ability to extend communication even to the inaccessible areas beyond communication range that lacks human intervention has made it even more attractive in a wide space of applications. Confined with numerous sensing nodes distributed over a wide area, the WSN incurs certain limitations as it is battery powered. Many developed routing enhancements with power and energy efficiency lacked in achieving the significant improvement in the performance. So, the paper proposes a machine learning system (capsule network) and technique (data pruning) for WSN involved in the real world observations to have knowledge‐based learning from the experience for an intelligent way of handling the dynamic and real environment without the intervention of the humans. The WSN cluster‐based routing aided with capsule network and data pruning proffered in paper enables the WSN to have a prolonged network lifetime, energy efficiency, minimized delay, and enhanced throughput by reducing the energy usage and extending communication within the limited battery availability. The proposed system is validated in the network simulator and compared with the WSN without ML to check for the performance enhancements of the WSN with ML inclusions in terms of quality of service enhancements, network lifetime, packet delivery ratio, and energy to evince the efficacy of the WSN with capsule network‐based data pruning.     

Contrôle de puissance dans les réseaux ad-hoc

In an ad-hoc network, mobile stations communicate with each other using multi-hop wireless links. There is no stationary infrastructure such as base stations. Each node in the network also acts as a router, forwarding data packets for other nodes. In this architecture, mobile stations have a multi-hop path, via other mobile stations acting as intermediaries or relays, to indirectly forward packets from source to destination. Adjusting the transmitted power is extremely important in ad-hoc networks due to at least the following reasons. The transmitted power of the radio terminals determines the network topology. The network topology in turn has considerable impact on the throughput (fraction of packets, sent by a source, and successfully received at the receiver) performance of the network. The need for power efficiency must be balanced against the lifetime of each individual node and the overall life of the network. Power control problem can be classified in one of three categories. The first class comprises of strategies to find an optimal transmitted power to control the connectivity properties of the network. The second class of approaches could be called power aware routing. Most schemes use some shortest path algorithm with a power based metric, rather than a hop count based metric. The third class of approaches aim at modifying the mac layer. We use distributed power control algorithms initially proposed for cellular networks. We establish a classification of power control algorithms for wireless ad-hoc networks. We evaluate these algorithms in anIeee 802.11b multi-hop wireless ad-hoc LAN environment. Results show the advantage of power control in maximizing signal-to-interference ratio and minimizing transmitted power.     

无线Ad hoc网络中基于节点位置的功率控制算法

为了降低无线Ad hoc网络中节点的能量消耗,该文提出了一种基于节点位置的功率控制算法(PCAP)。PCAP算法通过分析节点间的位置关系,建立节点的优化邻居集合,并对路由层报文、MAC层控制报文和其它数据类报文使用不同的功率控制策略。PCAP算法在保证网络连接性的同时能降低网络能量消耗,计算机仿真表明,PCAP算法在MAC层的吞吐量、MAC层丢包、端到端时延等方面取得较好的性能表现。     

移动自组织网络中基于树结构的优化组播路由算法(英)

Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.     

The multi-copy diversity for routing in sparse vehicular ad hoc networks

The need for routing based on store-and-carry forwarding has been motivated in sparse vehicular ad hoc networks (VANETs), since the traditional end-to-end unicast routing is infeasible due to the network disconnection problem. In store-and-carry based routing, the end-to-end message delivery delay is dominated by the store-and-carry procedure rather than the wireless transmission. Therefore, the end-to-end delay in such sparse VANETs can be further reduced by replicating multiple copies of the message to other nodes when possible, i.e., multi-copy routing, to increase the chance of finally finding the destination, which we call this gain as multi-copy diversity. In this paper, we present an analytic framework to evaluate the performance of routing by assessing the multi-copy diversity gain in sparse VANETs. By using this model, we first derive an upper and lower-bound of end-to-end routing delay in sparse VANETs. Our analytic results show that a high level of multi-copy diversity gain is achieved when the network is partially connected, which is in contrast to the conventional expectation that multi-copy routing performs better in severely disconnected networks. Second, we propose a new adaptive multi-copy VANET routing scheme called AMR by exploiting these analytic results. AMR adapts to the local network connectivity and increases the level of multi-copy diversity at significantly reduced routing overhead compared to the well known epidemic routing. We validate the accuracy of our analytic model and the performance of AMR via simulation studies.