The performance of query control schemes for the zone routingprotocol

We study the performance of route query control mechanisms for the zone routing protocol (ZRP) for ad hoc networks. The ZRP proactively maintains routing information for a local neighborhood (routing zone), while reactively acquiring routes to destinations beyond the routing zone. This hybrid routing approach can be more efficient than traditional routing schemes. However, without proper query control techniques, the ZRP cannot provide the expected reduction in the control traffic. Our proposed query control schemes exploit the structure of the routing zone to provide enhanced detection and prevention of overlapping queries. These techniques can be applied to single- or multiple-channel ad hoc networks to improve both the delay and control traffic performance of ZRP. Our query control mechanisms allow ZRP to provide routes to all accessible network nodes, with less control traffic than purely proactive link state or purely reactive route discovery, and with less delay than conventional flood searching     

Reliable Distributed Local Repair Approach for Maximizing Reliability and Packet Delivery Rate in Wireless on Demand AODV Networks

The most used protocol in Mobile Ad hoc Networks (MANETs) uses the Ad hoc On-Demand Distance Vector (AODV) routing protocol for achieving dynamic, self-organizing, and on-demand multihop routing. In AODV, wireless links may be lost occasionally because the nodes on the routing path are unreachable. Such a problem causes AODV inefficient and unreliable. For solving the problem, AODV provides a local repair mechanism for an intermediate node to find an alternative route to destination when the node detects links broken. The repair mechanism uses the broadcast-type RREQ message for discovering a repair route, which results in a large number of repair control messages and requires a large amount of power consumption for sending these messages. Therefore, in this paper we propose a unicast-type distributed local repair protocol for repairing breaks expeditiously, i.e., achieving high network reliability and utilization, less the number of control messages, and less the repair delay. Furthermore, the optimal number of hops in a neighbor table is analyzed. Numerical results indicate that the proposed approach is superior to other repair approaches in terms of successful fixing rate, control message overhead, and network utilization.     

Weighted dominating set based routing for ad hoc communications in emergency and rescue scenarios

Disasters create emergency situations and the services provided must be coordinated quickly via a communication network. Mobile adhoc networks (MANETs) are suited for ubiquitous communication during emergency rescue operations, since they do not rely on infrastructure. The route discovery process of on-demand routing protocols consumes too much bandwidth due to high routing overhead. Frequent route changes also results in frequent route computation process. Energy efficiency, quick response time, and scalability are equally important for routing in emergency MANETs. In this paper, we propose an energy efficient reactive protocol named Weighted-CDSR for routing in such situations. This protocol selects a subset of network nodes named Maximum Weighted Minimum Connected Dominating Set (MWMCDS) based on weight, which consists of link stability, mobility and energy. The MWMCDS provides the overall network control and data forwarding support. In this protocol, for every two nodes u and v in the network there exists a path between u and v such that all intermediate nodes belong to MWMCDS. Incorporating route stability into routing reduces the frequency of route failures and sustains network operations over an extended period of time. With fewer nodes providing overall network control and data forwarding support, the proposed protocol creates less interference and consumes less energy. The simulation results show that the proposed protocol is superior to other protocols in terms of packet delivery ratio, control message overhead, transmission delay and energy consumption.     

Moralism: mobility prediction with link stability based multicast routing protocol in MANETs

In recent research, link stability is getting tremendous attention in mobile adhoc networks (MANETs), because of several impediments that occur in a reliable and robust network. Link stability metric is used to improve network performance in terms of end-to-end delay, data success delivery ratio (DSDR) and available route time (ART). Energy consumption, bandwidth and communication delay of major concern in ad hoc networks. A high mobility of MANET nodes reduces the reliability of network communication. In a dynamic networks, high mobility of the nodes makes it very difficult to predict the dynamic routing topology and hence cause route/link failures. Multicast in MANETs is an emerging trend that effectively improves the performance while lowering the energy consumption and bandwidth usage. Multicast routing protocol transmits a packet to multicast a group at a given time instant to achieve a better utilization of resources. In this paper, node mobility is considered to map better their movement in the network. So, the links with long active duration time can be identified as a stable link for route construction. Variation in signal strength is used to identify whether the direction of the node is towards or away from estimating node. We consider signal strength as QoS metric to calculate link stability for route construction. Efforts are made to identify the link with highly probable longer lifetime as the best suitable link between two consecutive nodes. We predict the movement time of nodes that define the route path to the node destination. Exata/cyber simulator is used for network simulation. The simulation results of the proposed routing protocol are compared with on-demand multicast routing protocol and E-ODMRP, which works on minimum hop count path. Analysis of our simulation results has shown improvement of various routing performance metrics such as DSDR, ART, routing overhead and packet drop ratio.     

Dynamic Relationship-Zone Routing Protocol for Ad Hoc Networks

A new dynamic relationship-zone routing protocol (DRZRP) for ad hoc networks is proposed. In this protocol, each node in the network establishes a neighboring-zone with a radius of ρ hops, and activates a relationship-zone according to the service request frequency and service hotspot condition. DRZRP establishes proactive routing for neighboring-zone and relationship-zone of the node, and the relationship-zone of the node can be dynamically maintained, including: initialization, relationship-zone activation, and relationship-zone inactivation. The simulation results are compared with LSR, ZRP and ZHLS protocols, and DRZRP greatly reduces the communication overhead of routing control messages and significantly improves the average delay of routing requests. The new protocol matches the service relationship among nodes in the network, and has comprehensive performance advantage in communication overhead and routing request delay, which improves the quality of network service.

     

A routing layer-based hierarchical service advertisement and discovery for MANETs

The implementation of mobile ad hoc networks (MANETs) is steadily increasing. MANETs are especially popular in locations that lack a fixed communication infrastructure. To achieve zero-configuration MANETs, as well as quick and easy access to network resources, resources must be well managed by the network. This paper proposes a hierarchical service discovery and advertisement protocol (HSDAP) implemented in the routing layer. HSDAP queries services by piggybacking service REQuest (SREQ) packets on routing packets to reduce overhead and energy consumption. We extend the cluster-based routing protocol (CBRP) to improve service management hierarchy. Simulation results show that adding service discovery and advertisement (SDA) functions to CBRP does not significantly affect overhead. SDA overhead, routing overhead, energy consumption, and SDA delay are significantly less than the extended zone routing protocol. Furthermore, SDA hit ratio of the proposed protocol is greater than 86% for various levels of mobility. The proposed HSDAP is robust and scalable.     

Bayesian inference approach for establishing efficient routes in wireless ad-hoc networks

Mobile ad hoc networks (MANETs) are dynamic wireless networks that have no fixed infrastructures and do not require predefined configurations. In this infrastructure-less paradigm, nodes in addition of being hosts, they also act as relays and forward data packets for other nodes in the network. Due to limited resources in MANETs such as bandwidth and power, the performance of the routing protocol plays a significant role. A routing protocol in MATET should not introduce excessive control messages to the network in order to save network bandwidth and nodes power. In this paper, we propose a probabilistic approach based on Bayesian inference to enable efficient routing in MANETs. Nodes in the proposed approach utilize the broadcast nature of the wireless channel to observe the network topology by overhearing wireless transmissions at neighboring nodes in a distributed manner, and learn from these observations when taking packet forwarding decision on the IP network layer. Our simulation results show that our routing approach reduces the number of control message (routing overhead) by a ratio up to 20 % when the network size is 60 nodes, while maintaining similar average route establishment delay as compared to the ad-hoc on demand routing protocol.     

无线网络中一种高QoS保证的路由协议研究

随着多媒体及实时应用的普及,在移动自组网中为业务流提供服务质量保证现已成为研究热点.提出一种在大规模移动自组网中提供服务质量保证的分段式路由协议.该协议采用直线逼近的方法,逐段建立满足带宽要求且延迟小的路径,并选择到源节点和目的节点连线距离最近的节点作为转发节点.通过分段、独立地维护路由,减小了路由维护的代价,提高了可扩展性.模拟结果表明该路由协议具有路由成功率高、路径短和延迟小等特点.     

DOA: DSR over AODV Routing for Mobile Ad Hoc Networks

We present a lightweight hierarchical routing model, Way Point Routing (WPR), in which a number of intermediate nodes on a route are selected as waypoints and the route is divided into segments by the waypoints. Waypoints, including the source and the destination, run a high-level intersegment routing protocol, while the nodes on each segment run a low-level intrasegment routing protocol. One distinct advantage of our model is that when a node on the route moves out or fails, instead of discarding the whole original route and discovering a new route from the source to the destination, only the two waypoint nodes of the broken segment have to find a new segment. In addition, our model is lightweight because it maintains a hierarchy only for nodes on active routes. On the other hand, existing hierarchical routing protocols such as CGSR and ZRP maintain hierarchies for the entire network. We present an instantiation of WPR, where we use DSR as the intersegment routing protocol and AODV as the intrasegment routing protocol. This instantiation is termed DSR over AODV (DOA) routing protocol. Thus, DSR and AODV—two well-known on-demand routing protocols for MANETs—are combined into one hierarchical routing protocol and become two special cases of our protocol. Furthermore, we present two novel techniques for DOA: one is an efficient loop detection method and the other is a multitarget route discovery. Simulation results show that DOA scales well for large networks with more than 1,000 nodes, incurring about 60 percent-80 percent less overhead than AODV, while other metrics are better than or comparable to AODV and DSR.     

低开销的MANET网络按需路由协议

针对简单泛洪效率低的问题,提出了一个限制洪泛的高效的路由广播算法,通过Euclidean距离来限制路由发现过程中请求分组被转发的次数;研究了减少路由维护开销,并降低路由发现的频率的方法,提出了一个基于节点高度的路由修复与优化算法,该算法使用节点监听来对链路断裂的路由进行修复与优化.基于限制泛洪的高效的路由广播算法和路由修复优化算法,提出了一种新的低开销的MANET网络按需路由协议LOOR(low overhead on-demand routing).仿真结果表明,新协议增强了路由的顽健性,减少了路由跳数,降低了路由发现的频率,提高了数据分组递送率,并显著地降低了路由控制开销.     

HOPNET: A hybrid ant colony optimization routing algorithm for mobile ad hoc network

Mobile ad hoc network (MANET) is a group of mobile nodes which communicates with each other without any supporting infrastructure. Routing in MANET is extremely challenging because of MANETs dynamic features, its limited bandwidth and power energy. Nature-inspired algorithms (swarm intelligence) such as ant colony optimization (ACO) algorithms have shown to be a good technique for developing routing algorithms for MANETs. Swarm intelligence is a computational intelligence technique that involves collective behavior of autonomous agents that locally interact with each other in a distributed environment to solve a given problem in the hope of finding a global solution to the problem. In this paper, we propose a hybrid routing algorithm for MANETs based on ACO and zone routing framework of bordercasting. The algorithm, HOPNET, based on ants hopping from one zone to the next, consists of the local proactive route discovery within a node’s neighborhood and reactive communication between the neighborhoods. The algorithm has features extracted from ZRP and DSR protocols and is simulated on GlomoSim and is compared to AODV routing protocol. The algorithm is also compared to the well known hybrid routing algorithm, AntHocNet, which is not based on zone routing framework. Results indicate that HOPNET is highly scalable for large networks compared to AntHocNet. The results also indicate that the selection of the zone radius has considerable impact on the delivery packet ratio and HOPNET performs significantly better than AntHocNet for high and low mobility. The algorithm has been compared to random way point model and random drunken model and the results show the efficiency and inefficiency of bordercasting. Finally, HOPNET is compared to ZRP and the strength of nature-inspired algorithm is shown.     

A QoS Routing Protocol with Bandwidth Allocation in Multichannel Ad Hoc Networks

Mobile multimedia applications have recently generated much interest in mobile ad hoc networks (MANETs) supporting quality-of-service (QoS) communications. Multiple non-interfering channels are available in 802.11 and 802.15 based wireless networks. Capacity of such channels can be combined to achieve higher QoS performance than for single channel networks. The capacity of MANETs can be substantially increased by equipping each network node with multiple interfaces that can operate on multiple non-overlapping channels. However, new scheduling, channel assignment, and routing protocols are required to utilize the increased bandwidth in multichannel MANETs. In this paper, we propose an on-demand routing protocol M-QoS-AODV in multichannel MANETs that incorporates a distributed channel assignment scheme and routing discovery process to support multimedia communication and to satisfy QoS bandwidth requirement. The proposed channel assignment scheme can efficiently express the channel usage and interference information within a certain range, which reduces interference and enhances channel reuse rate. This cross-layer design approach can significantly improve the performance of multichannel MANETs over existing routing algorithms. Simulation results show that the proposed M-QoS-AODV protocol can effectively increase throughput and reduce delay, as compared to AODV and M-AODV-R protocols.     

一种基于功耗考虑的自组网路由算法研究

对移动自组网中路由协议的负载均衡问题进行了分析与研究,并以区域路由协议(ZRP)为基础,引入负载均衡的思想,对主动式部分的路由策略进行了算法改进。仿真结果证明,该算法在对路由开销没有明显增加以及算法复杂度不变的情况下,使得网络节点的功耗性能得到了很大的改善与提升。     

GMZRP: Geography-aided Multicast Zone Routing Protocol in Mobile Ad Hoc Networks

This paper presents the design and evaluation of a highly efficient on-demand multicast routing protocol for mobile ad hoc networks (MANETs). The protocol, called Geography-aided Multicast Zone Routing Protocol (GMZRP), eliminates as much as possible duplicate route queries by using a simple yet effective strategy for propagating the multicast route request (MRREQ) packets. GMZRP is the first hybrid multicast protocol taking the advantages of both topological routing and geographical routing. It partitions the network coverage area into small zones and guarantees that each geographic zone is queried only once. GMZRP maintains a multicast forwarding tree at two levels of granularities, i.e., the zone granularity and the node granularity. By doing this, it can easily handle route breakage since the zone level information can help recover the link failure at the node level. The results of the performance evaluation of GMZRP using simulation show that, comparing with the well-known multicast protocol ODMRP (On-Demand Multicast Routing Protocol), GMZRP has much lower protocol overhead in terms of query packets and, meanwhile, achieves competing packet delivery ratio and shorter delivery latency.

A Minimum Interference Cross-Layer Routing Protocol for Mobile Ad Hoc Networks

In mobile ad hoc networks (MANETs), channel contention and packet collision can seriously affect the performance of routing protocols, which will eventually affect the performance of the whole network. Besides, the arbitrary mobility of nodes makes contention and collision ever-changing and more complex. Thus, it is imperative to analyze the problem of contention and collision so as to build appropriate routes in MANETs. In this paper, by respectively predicting the durations of the contention and collision at every hop along the route, a minimum interference cross-layer routing protocol (MI-CLR) is proposed based on Random Waypoint (RWP) model. The new protocol classifies the interference in the network into two types; the first type of interference can only affect channel contention, while the other affects both channel contention and packet collision. Via taking the two types of interference together into account, we propose a new routing metric to build routes which guarantees that the established routes will not break frequently while having the minimum interference. Simulation results show that the MI-CLR protocol can significantly improve the network performance such as the average end-to-end delay, the packet loss ratio, the routing overhead and the throughput.     

Determining the optimal configuration for the zone routing protocol

The zone routing protocol (ZRP) is a hybrid routing protocol that proactively maintains routes within a local region of the network (which we refer to as the routing zone). Knowledge of this routing zone topology is leveraged by the ZRP to improve the efficiency of a reactive route query/reply mechanism. The ZRP can be configured for a particular network through adjustment of a single parameter, the routing zone radius. We address the issue of configuring the ZRP to provide the best performance for a particular network at any time. Previous work has demonstrated that an optimally configured ZRP operates at least as efficiently as traditional reactive flood-search or proactive distance vector/link state routing protocols (and in many cases, much more efficiently). Adaptation of the ZIP to changing network conditions requires both an understanding of how the ZRP reacts to changes in network behavior and a mechanism to allow individual nodes to identify these changes given only limited knowledge of the network behavior. We demonstrate the effects of relative node velocity, node density, network span, and user data activity on the performance of the ZRP. We then introduce two different schemes (“min searching” and “traffic adaptive”) that allow individual nodes to identify and appropriately react to changes in network configuration, based only on information derived from the amount of received ZRP traffic. Through test-bed simulation, we demonstrate that these radius estimation techniques can allow the ZRP to operate within 2% of the control traffic resulting from perfect radius estimation     

Combining on-demand and opportunistic routing for intermittently connected networks

While current on-demand routing protocols are optimized to take into account unique features of mobile ad-hoc networks (MANETs) such as frequent topology changes and limited battery life, they often do not consider the possibility of intermittent connectivity that may lead to arbitrarily long-lived partitions. In this work, we introduce the space-content-adaptive-time routing (SCaTR) framework, which enables data delivery in the face of both temporary and long-lived MANET connectivity disruptions. SCaTR takes advantage of past connectivity information to effectively route traffic towards destinations when no direct route from the source exists. We show through simulations that, when compared to traditional on-demand protocols, as well as opportunistic routing (e.g., epidemic), SCaTR increases delivery ratio with lower signaling overhead in a variety of intermittently connected network scenarios. We also show that SCaTR performs as well as on-demand routing in well-connected networks and in scenarios with no mobility predictability (e.g., random mobility). In the latter case, SCaTR delivers comparable reliability to epidemic routing with considerably lower overhead.     

Status adaptive routing with delayed rebroadcast scheme in AODV-based MANETs

An efficient solution is proposed in this article to determine the best reliable route and to prolong the lifetime of the mobile Ad-hoc networks （MANETs）. In the proposed solution, the route discovery process of the Ad-hoc on-demand distance vector routing protocol （AODV） has been modified using a novel delayed rebroadcast scheme. It combines the shortest route selection criterion of AODV with the real network status including the wireless link quality, the remaining power capacity, as well as the traffic load at each node. Simulation results show that the proposed scheme can significantly extend the network lifetime and provide fewer packet losses than the conventional AODV protocol.     

一种基于路径信息的WSN路由协议

AODV是一种广泛应用于MANET的按需路由协议,但是它并不完全适用于WSN。本文通过改进AODV协议基于洪泛的路由机制,提出了一种适用于WSN的低开销、低时延的路由协议IAODV。仿真结果表明:与AODV协议相比,IAODV协议可以在保持较高的分组投递率的同时有效降低数据分组的平均端到端时延和路由开销,达到了低开销、低时延的设计目标。