Effective OFDMA Based Signaling in Ad-Hoc Wireless Networks

The year 2005 witnesses the third occasion that the Wireless Personal Area and Ad-hoc Networks minitrack is part of the annual HICSS conference. This year there was a substantial increase in submissions (thus a substantial decrease in the acceptance rate), indicating the growing importance of research in this area. The minitrack is also focused on fundamental challenges and issues arising in wireless sensor networks and their applications. Wireless sensor networks differ from other wireless networks in the need for unattended and very low-energy operation, in the possibility of collaboration and distributed sensor calibration, and in the mission oriented nature of most sensor networks. Thus our mini track looks at two very important streams of research. After a strict review process nine papers were selected to be included in the program of the minitrack. The first paper is titled “BT-Crowds: Crowds-style Anonymity with Bluetooth and Java,” presenting an interesting idea on how anonymity can be achieved when sending messages in WPAN environments. Our second paper revisits scatternet formation issues of Bluetooth based ad hoc networks thus the title: “A Dynamic and Distributed Scatternet Formation Protocol for Real-life Bluetooth Scatternets.” The third paper is titled “Secure Dynamic Source Routing” and presents a new variant of the DSR routing protocol with special emphasis on security. In the fourth paper, the discussion concerns “Routing Based Feedback towards Applications in Mobile Ad Hoc Networks,” where routing notifications are relayed via event channels. “A Location Service Mechanism for Position-Based Multicasting in Wireless Mobile Ad hoc Networks” is the title of the fifth paper in the minitrack. It presents some innovative ideas on how location information can be managed for multicast communications in ad-hoc networks. In the sixth paper, “Sliding Window Protocol for Secure Group Communication in Ad Hoc Networks,” the authors propose a sliding window protocol for determining multiple routes in a multi-communications environment. In the seventh paper titled “Ad Hoc Routing Protocol Avoiding Route Breaks Based on AODV,” the authors propose improvements to the well-known AODV ad hoc routing protocol The eight paper, “Joint Scheduling and Routing Algorithm for Ad Hoc Wireless,” presents an innovative and interesting idea wrapped around an iterative algorithm on power control. In the final paper of the minitrack, “Performance Issues of Ad Hoc Routing Protocols in a Network Scenario used for VideoPhone Applications,” the authors present a simulation based performance analysis of different ad hoc routing protocols using the application pointed to in the title. These papers highlight some of the issues and work towards solutions in Personal Area and ad hoc networks which are among the most active research fields in wireless networking. We believe that the papers will provide opportunities for researchers to come together and discuss and debate the results of the interesting experiments that are described in the papers. We are confident that the minitrack will achieve its goal of bringing together leading researchers, to present new results and discuss synergies between the two areas. We also take this opportunity to thank all the reviewers for their valuable and professional work as well as all the authors who submitted papers and thus helped us to create such a strong minitrack. We would also like to express our sincere gratitude to the conference organizers for their hard work and help.

Recent development has a tremendous growth in the ad-hoc wireless networks. Ad-hoc wireless networks are dynamic topology networks organized by a collection of mobile nodes that utilize multi-hop radio relaying and are capable of operating without the support of any fixed infrastructure. Ad-hoc wireless networks are very useful in emergency operations, collaborative and distributed computing and military applications. Multicasting plays an important role in the ad-hoc wireless networks, where nodes form groups to carry out certain tasks that require point-to-multipoint and multipoint-to-multipoint voice and data communication. The biggest challenge in the ad-hoc wireless networks is to find an optimized path between the two nodes. In this paper, we present an ant colony based metaheuristic multicast routing protocol for ad-hoc wireless networks, in that we analyzed the performance of dynamic core based multicast routing protocol (DCMP). This approach maps the solution capability of swarm intelligence to mathematical and engineering problems. The DCMP is highly adaptive, efficient and scalable. The performance of these protocols has been examined under realistic scenarios using NS 2, the network simulator tool. Performance has been analyzed for the metrics packet delivery ratio and control overheads with the multicast routing protocol. The proposed ant colony based routing protocol reduce the overheads in routing.

Minimizing interference of a wireless ad-hoc network in a plane

Ad-hoc networks are completely wireless networks of mobile hosts, in which the topology rapidly changes due to the movement of mobile hosts. This frequent topology may lead to sudden packet losses and delays. Transport protocols like TCP have been built mainly for reliable, fixed networks. Hence, when used in ad-hoc networks, TCP misinterprets this loss as congestion and invokes congestion control. This leads to unnecessary retransmissions and loss of throughput. To overcome this problem, a feedback scheme is proposed, so that the source can distinguish between route failure and network congestion. When a route is disrupted, the source is sent a route failure notification (RFN) packet, allowing it to freeze its timers and stop sending packets. When the route is re-established, the source is informed through a route re-establishment notification (RRN) packet, upon which it resumes by unfreezing timers and continuing packet transmissions. The simulated performance of TCP on ad-hoc networks with and without feedback is compared and reported. It is observed that in the event of route failures, as the route re-establishment time increases, the use of feedback provides significant gains in throughput as well as savings in unnecessary packet transmissions. Several further enhancements and directions for future work are also sketched.

Recent demands on affordable, portable wireless communication and computation devices have resulted in exponential growth of wireless networks ranging from Wireless Local Area Networks (WLAN) and Wireless Wide Area Networks (WWAN) to Ad-Hoc and Sensor networks. The major goal of wireless communication is to allow users to communicate together and to have access to global network anytime anywhere. This has led to wide acceptance of infrastructure based cellular networks (WWANs) where mobile stations communicate with a centralized controller, often referred as Access Point (AP) that is connected to the wired networks. On the other hand, WLANs have appeared as dominant popular technologies in many venues including a local area such as an academic campus or an airport terminal. These wireless networks mostly rely on IEEE 802.11 Wi-Fi (Wireless Fidelity) technology and its various derived versions (i.e. 802.11a,b,g). IEEE 802.11 standard supports two operational modes: The infrastructure-based Wireless Local Area Networks (WLANs) and an infrastructure-less Ad-Hoc Networks. A WLAN (Conti, 2003) typically imposes the existence of an AP and normally is connected to the wired networks to provide internet access for mobile devices. Obviously, only one hop link is needed to communicate between mobile devices and AP. In contrast, there is no AP or infrastructure in Ad-Hoc networks. Any two stations can communicate directly when they are in the range of reception of each other. To this end, the stations may use multi-hop routing to deliver their packets to destinations. The ad-hoc protocols (Conti, 2003; Mohapatra & Krishnamurthy, 2005) are self-configured for address and routing in the face of mobility and the network topology may change in each configuration. The multi-hop wireless ad-hoc networks, or multi-hop wireless networks enable wireless networking in the environments where the wired or cellular connections are impossible, inadequate, or cost effective (e.g. battle field, disaster recovery, etc.). The popularity of internet over the last decades has resulted in rapid advancement of demanding applications. The Transmission Control Protocol/Internet Protocol (TCP/IP) (Stevens, 1994) is a well-known de facto protocol in developing today’s internet. Basically, TCP provides a connection-oriented and reliable end-to-end data delivery between two hosts in traditional wired networks. Since TCP is well tuned and due to its wide acceptance in internet, it is desirable to extend and adopt its functionality to wireless networks. On the

Ad-hoc 네트워크 환경에서의 많은 라우팅 알고리즘들은 소스 라우팅 기법을 기초로 설계되었으며 밀집된 ad-hoc 환경에서의 최단경로설정은 짧은 기간동안만 유지되는 제약사항이 존재한다 때문에 SSA와 ABR과 같은 라우팅 프로토콜은 링크 안정성을 고려하여 좀더 안정적인 경로를 탐색한다. 본 논문은 Ad-Hoc network 환경에 현실적으로 적합한 SSA 라우팅 알고리즘을 바탕으로 utilization 메트릭을 고려한 새로운 라우팅 기법에 대해 제안한다. 제안된 방식에서는 SSA의 특정 메트릭에 의한 병목현상을 해결하기 위해 연결을 위한 여러 경로들을 누적 utilization에 따라 분산시키도록 하여 네트워크상의 로드 밸런싱을 추구하였다. 성능 분석을 위해 기존의 라우팅 기법인 AODV와 SSA를 참고 비교 대상으로 하였다. ns-2 네트워크 시뮬레이션 결과 선택되어질 수 있는 안정적인 route가 많은 경우 전체 트래픽이 여러 경로들로 분산되어 경로 재설정(route reconstruction) 횟수를 현저히 줄이는 좋은 성능을 보였다 Many routing algorithms, proposed for ad-hoc wireless networks, we based on source routing scheme and shortest path route has short lifetime especially in highly dense ad-hoc wireless networks. So some routing protocols such as SSA and ABR are considering the link stability and try finding more stable route. In this paper we propose a new routing algorithm considering utilization metric based on SSA routing algerian in Ad-Hoc networks. To reduce the bottleneck by specific metric of SSA, proposed scheme makes load balancing in networks by distributing the connections to several routes. For the evaluation of the performance we compare our scheme with existent routing protocol AODV and SSA. And the results, obtained using the ns-2 network simulation platform, show good performance that reduced the number of reconstructions remarkably by distributing the whole traffic to several routes when there are several stable routes.

Broadcasting is an essential operation for Wireless Ad Hoc Networks to perform routing path discovery, and it has become the predominant technology for message dissemination in Vehicular Ad Hoc Networks (VANETs). In the reactive routing schemes of wireless ad hoc network, Routing Request (RREQ) packets are broadcast from the source, and once received the destination traces back the broadcasting path to build an on-demand route. In VANETs, different broadcasting schemes have been proposed for safety, comfort, and commercial applications. However, broadcasting usually generates a lot of redundant messages which would cause excessive channel contention and packet collisions, especially when the density of the network becomes higher. In this survey article, we first introduce the most common data dissemination techniques used in wireless ad hoc networks. After that, we discuss techniques that have been proposed to mitigate the broadcast storm problem. Finally, we introduce an effective model for analyzing the broadcasting schemes, and based on the model we propose an adaptively adjusted probabilistic scheme that highly improves the reliability of broadcasting in dense ad hoc networks.

An ad-hoc wireless network is formed by a number of mobile nodes having limited communication range. The dynamic source routing (DSR) protocol is frequently used to extend the effective range of these nodes through mutual cooperation. The accurate execution of the DSR protocol demands sustained benevolent behaviour by all participating nodes. However, as ad-hoc networks are created in improvised environments, the realization of such altruistic behaviour is virtually impossible to achieve. In fixed networks, trust infrastructures like certification authorities and key distribution centres are generally used to provide default trust relationships. However, the creation of such an entity in an ad-hoc network is considered neither feasible nor pragmatic. In this paper, we propose a novel mechanism for establishing trust based routing in ad-hoc networks without necessitating a trust infrastructure. We accentuate, that the proposed mechanism is most suitable for ad-hoc networks that can be created on the fly without making any suppositions or imposing pre-configuration requirements.

VANET (Vehicular Ad-hoc Network) is an ad-hoc wireless network which nodes are composed by mostly moving vehicles and infrastructure communications or access points along the road. It integrates adhoc networking, cellular technology, wireless LAN and other technologies, which include GPS(Global Positioning System), digital mapping, sensing technologies and advanced information processing tools to support Intelligent Traffic Systems (ITS). VANET is developed mainly to improve road safety and to increase the traffic efficiency. It is designed to support the exchange of warning messages among the vehicles to increase the passenger safety and other information related to VANET applications and services . To achieve these goals, there are several issues that should be addressed. One of these challenges is designing reliable and efficient Medium Access Control (MAC) protocol for VANET. Due to VANET’s distinguishing characteristics, such as high mobility of the nodes, dynamic network topology, enough battery power, high processing power, etc, the MAC protocols designed for MANET (Mobile Ad-hoc Network) are not suitable for VANET. The research community has been working to develop MAC protocols appropriate for this ad-hoc network by proposing new design or modifying the existing one.In this paper, the VANET’s architecture, characteristics, applications and standard are discussed and then a comprehensive study of several MAC protocols available in the literature is presented.

In wireless mobile ad-hoc networks, data packets have to be relayed hop by hop from a given source node to a destination node. This means that some or all of the mobile nodes must accept to forward information for the benefit of other nodes. It has been shown by F. Nait-Abdesselam, et al., (2003) that this ability of forwarding packets leads to a new unfairness problem in wireless ad-hoc networks, where a node which is forwarding other node's packets gets less bandwidth, for its own use, than a node which is not participating to the routing service. The proposed RAMAC scheme by F. Nait-Abdesselam, et al., (2003), has shown all its effectiveness to cope with this unfairness problem. However, an extra bandwidth is sometimes allowed to the routing node's own traffic comparing to other nonrouting node's own traffics, and the routing node's routed traffic gets much less bandwidth. This is explained by the fact that at the upper layer (for instance the IP layer) does not differentiate between the routing and the own traffics, and that the multiplicative factor used to compute the new contention window is too aggressive. In this paper, an enhanced RAMAC scheme is proposed, by taking into account the differentiation on top of the MAC layer, between the and routed traffics within a routing node, and by smoothing the multiplicative factor used to compute the new contention window. The simulation results obtained showed a good improvement of the original RAMAC scheme, leading to better approximate equal bandwidth share among all the mobile nodes in the wireless ad-hoc network.

Ad Hoc network is one of the popular wireless multi-hop networks. Nodes or Users in Ad Hoc network can move randomly and freely to maintain communication without the control of the fixed infrastructure. Due to the limited transmission power and wireless coverage of the terminal, if two terminals that are beyond their respective transmission radius need communicate, they must use other intermediate or relay nodes for packet forwarding, so that a wireless Ad Hoc network is formed among these nodes. In this paper, the current state-of-the-art multipath routing protocols for Ad Hoc networks are reviewed. Particularly, the pros and cons of them are analyzed. Finally, they are summarized and compared.

In recent years, with the increasing popularity of Internet technology and the advent of the 5G communication era, the applications related to mobile IoT have exploded, and wireless Ad Hoc network has received more and more attention. In traditional Ad Hoc networks, data are often transmitted between nodes in the form of "multi-hops", and the transmission range and available energy of nodes are limited. Thus, in Ad Hoc networks, a reliable and energy-efficient data transmission protocol is needed. In this paper, we studied the existing multipath routing protocols and proposed a multiple performances based routing protocol E <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> LR, ( residual Energy, Energy consumption, Loop, Routing protocol ) for the shortcomings of Ad Hoc networks. This protocol has the following improvements to the existing multi-path routing protocols: (1) In the route discovery process, depending on the energy level of the nodes, the nodes make three different decisions on the received RREQ packets: discard, randomly delayed forwarding, and immediate forwarding, to filter out the nodes with lower energy and thus improve the network performance. (2) When selecting available paths, try to select nodes whose lifetime are close to each other. This can reduce the number of interruptions in the transmission path and improve the stability of the transmission path during data transmission. (3) When transmitting data, multiple paths stored in the source node are recycled to transmit data, thus balancing the node energy. Simulation results show that the E2LR routing protocol can effectively reduce the frequency of route initiation, shorten the data transmission delay, reduce the packet loss rate in the network compared with existing multipath routing protocols.

Geographic routing protocols establish scalable and robust routes for multi-hop trsdansmission in wireless mobile ad-hoc networks, where accurate location information of the mobile nodes is needed. Aiming to alleviate the influence of location errors, existing works focus on modifying routing protocols through modeling the error sources and mobility prediction. In this paper, we propose a cooperative cluster based geographic routing (CCGR) protocol, which views the cooperative cluster as one virtual relay node, and lessens the impact of location errors through opportunistic receiving and cooperative radio range extension. Opportunistic receiving achieves the link diversity and radio range extension enlarges the transmission distance of one hop. The performance of CCGR is analyzed under scenarios of both static and mobility location errors in terms of reliability index, which is defined to represent the link stability. Further more, numerical results demonstrate that our proposed transmission scheme CCGR outperforms non-cooperative routing schemes in terms of link error probability with location errors.

Using ad hoc networks as alternative means of communication in disaster situations is a salutary solution. However, analysing application performance is mandatory for evaluating such a possibility. In this paper we present the two aspects of our approach to application performance assessment on wireless ad hoc networks. The first aspect refers to real-world tests in which we quantify objectively the relationship between network conditions and application performance. The second aspect is represented by the wireless network (WLAN) emulator that we design to run on StarBED, the large-scale network experiment environment of the Hokuriku Research Centre in Ishikawa, Japan. By combining these two aspects we perform experiments with real applications, while having full control of the network conditions in which the application is tested (when using emulation).

Mobile Ad-hoc Network (MANET) has emerged as the self organized wire less interconnection for the various applications in random topology. As most of the multimedia applications require strict QoS guarantee during the communication between a single source and multiple destinations. How ever, achieving reliable multicast transmission in MANET is crucial due to the dynamic network topology caused by the node mobility. This gives rise to the need for an efficient multicast routing strategy. This paper proposes a novel scheme PBMRP-BR (position-based Multicast Routing Protocol for Ad-hoc Network Using Backpressure Restoration) for efficient transmission of multimedia applications in Ad-hoc Network, which provides priorities for routing based on Distance of path, Load at the node (ie, traffic) and queue length at the node(ie, bandwidth). It also keeps the path information including bandwidth resources of each node for routing decisions. The problem of the link failure in the channel during the call in progress thus lead in the degradation of the QoS (Quality of Service).To deal this we are using a Backpressure Technique The simulation results shows that the proposed algorithm is able to find a better solution, fast convergence speed and high reliability. The simulation results shows the proposed PBMRP-BR protocol achieve the above objectives and gives the batter results than previous schemes like DSR for the maintenance of overheads and the path reliability. Our proposed scheme will improve the bandwidth utilization by reducing the congestion in the Adhoc wireless network.