Showing papers on "Ad hoc wireless distribution service published in 1998"

A performance comparison of multi-hop wireless ad hoc network routing protocols

Abstract: An ad hoc networkis a collwtion of wirelessmobilenodes dynamically forminga temporarynetworkwithouttheuseof anyexistingnetworkirrfrastructureor centralizedadministration.Dueto the limitedtransmissionrange of ~vlrelessnenvorkinterfaces,multiplenetwork“hops”maybe neededfor onenodeto exchangedata ivithanotheracrox thenetwork.Inrecentyears, a ttiery of nelvroutingprotocols~geted specificallyat this environment havebeen developed.but little pcrfomrartwinformationon mch protocol and no ralistic performancecomparisonbehvwrrthem ISavailable. ~Is paper presentsthe results of a derailedpacket-levelsimulationcomparing fourmulti-hopwirelessad hoc networkroutingprotocolsthatcovera range of designchoices: DSDV,TORA, DSR and AODV. \Vehave extended the /~r-2networksimulatorto accuratelymodelthe MACandphysical-layer behaviorof the IEEE 802.1I wirelessLANstandard,includinga realistic wtrelesstransmissionchannelmodel, and present the resultsof simulations of net(vorksof 50 mobilenodes.

Location-aided routing (LAR) in mobile ad hoc networks

Abstract: A mobile ad hoc network consists of wireless hosts that may move often. Movement of hosts results in a change in routes, requiring some mechanism for determining new routes. Several routing protocols have already been proposed for ad hoc networks. This report suggests an approach to utilize location information (for instance, obtained using the global positioning system) to improve performance of routing protocols for ad hoc networks.

Power-aware routing in mobile ad hoc networks

Abstract: b this paper we present a case for using new power-aware metn.cs for determining routes in wireless ad hoc networks. We present five ~erent metriw based on battery power consumption at nodw. We show that using th=e metrics in a shortest-cost routing algorithm reduces the cost/packet of routing packets by 5-30% over shortwt-hop routing (this cost reduction is on top of a 40-70% reduction in energy consumption obtained by using PAMAS, our MAC layer prtocol). Furthermore, using these new metrics ensures that the mean time to node failure is increased si~cantly. An interesting property of using shortest-cost routing is that packet delays do not increase. Fintiy, we note that our new metrim can be used in most tradition routing protocols for ad hoc networks.

PAMAS—power aware multi-access protocol with signalling for ad hoc networks

Abstract: In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10% and 70% are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well.

Comparative performance evaluation of routing protocols for mobile, ad hoc networks

Abstract: We evaluate several routing protocols for mobile, wireless, ad hoc networks via packet level simulations. The protocol suite includes routing protocols specifically designed for ad hoc routing, as well as more traditional protocols, such as link state and distance vector used for dynamic networks. Performance is evaluated with respect to fraction of packets delivered, end-to-end delay and routing load for a given traffic and mobility model. It is observed that the new generation of on-demand routing protocols use a much lower routing load. However the traditional link state and distance vector protocols provide, in general, better packet delivery and delay performance.

Spine routing in ad hoc networks

Abstract: An ad hoc network is a multihop wireless network in which mobile hosts communicate without the support of a wired backbone for routing messages. We introduce a self organizing network structure called a spine and propose a spine-based routing infrastructure for routing in ad hoc networks. We propose two spine routing algorithms: (a) Optimal Spine Routing (OSR), which uses full and up-to-date knowledge of the network topology, and (b) Partial-knowledge Spine Routing (PSR), which uses partial knowledge of the network topology. We analyze the two algorithms and identify the optimality-overhead trade-offs involved in these algorithms.

Multicast routing issues in ad hoc networks

Abstract: The advent of ubiquitous computing and the proliferation of portable computing devices have raised the importance of mobile and wireless networking. At the same time, the popularity of group-oriented computing has grown tremendously. However, little has been accomplished to-date in bringing together the technologies for group-oriented communication and mobile networking. In particular, most modern wireless/mobile and ad hoc networks do not provide support for multicast communication. A major challenge lies in adapting multicast communication to environments where mobility is unlimited and outages/failures are frequent. This paper motivates the need for new multicast routing protocols aimed specifically at fully-mobile (ad hoc) networks. Our premise is that, due to their inherent broadcast capability, wireless networks are well-suited for multicast communication. Unlike the evolution of routing in wired networks, we believe that-in ad hoc networks-it is more effective to treat multicast routing as a separate problem. The paper also identifies outstanding research issues pertaining to multicast routing in mobile and ad hoc networks, and discusses one possible approach to multicast routing and packet forwarding in ad hoc networks.

The clade vertebrata: spines and routing in ad hoc networks

Abstract: This work proposes a self-organizing, dynamic infrastructure called a spine for efficient routing in ad hoc networks. We present a scalable framework for routing that encompasses a range of knowledge at each spine node, and identify the trade-offs involved for routing at different points in this range. Our routing algorithm requires only partial topology information at each spine node, consisting of the spine structure, dependants of each spine node, propagation of long-lived links, and snooped routing information from ongoing flows. Through worst-case theoretical bounds and simulation of typical scenarios, we show that the spine-based routing with only partial topology information provides good routes at low overhead.

Core Extraction Distributed Ad hoc Routing (CEDAR) Specification

Abstract: This draft presents CEDAR, a Core-Extraction Distributed Ad hoc Routing algorithm for QoS routing in ad hoc network environments. CEDAR has three key components: (a) the establishment and maintenance of a self-organizing routing infrastructure, called the "core", for performing route computations, (b) the propagation of the link-state of stable high-bandwidth links in the core through "increase/decrease" waves, and (c) a QoS route computation algorithm that is executed at the core nodes using only locally available state. Sivakumar, Sinha, Bharghavan [Page 1] INTERNET-DRAFT CEDAR Specification October 1998

K-hop cluster-based dynamic source routing in wireless ad-hoc packet radio network

Abstract: The existing wireless networks, such as cellular networks, personal communication services and mobile Internet protocol use the fixed network as their backbones. However in the situations like disaster rescues, wireless conferences in the hall, or battlefields, there exists no fixed communication infrastructure. Therefore, routing to send data packets to their destinations becomes very difficult. Distance vector and link state protocols used in the existing fixed networks are not suitable for supporting host movements. Variations of distance vector protocol, dynamic source muting schemes, and cluster-based schemes have been suggested to solve the muting problem in this entirely wireless network. However, since the link channel resource is very scarce, the muting scheme must consider the overall channel utilization as well as host mobility. We present a generalized approach called "k-hop cluster-based dynamic source routing". This approach is simple and can take actions on the host movements quickly.

An Evolutionary-TDMA Scheduling Protocol (E-TDMA) for Mobile Ad Hoc Networks

Abstract: A new single channel, time division multiple access (TDMA) scheduling protocol, termed “EvolutionaryTDMA”, is presented for mobile ad hoc networks. The protocol allows nodes in an ad hoc network to reserve conflict-free TDMA slots for transmission to their neighbors. Two topology-dependent schedules are generated and maintained by the protocol: a broadcast schedule suitable for network control traffic and a mixed schedule which combines unicast, multicast and broadcast transmissions for user data traffic. The schedules are frequently updated in an evolutionary manner to maintain conflict-free transmissions. The protocol executes across the entire network simultaneously in a fully-distributed and parallel fashion. Traffic prioritization and Quality of Service (QoS) can be supported. Simulations have shown that the performance of the E-TDMA protocol is close to that of centralized algorithms, while being insensitive to network size in terms of scheduling quality and scheduling overhead. It is a scalable protocol suitable for very large networks, and networks of varying size.

Efficient communication strategies for ad-hoc wireless networks (extended abstract)

Abstract: An ad-hoc wireless network is a collection bile hosts forming a temporary network wi any established infrastructure or centralized This type of network is of great importan in situations where it is very difficult to provide the necessa ture, but it is a challenging task able communication within such a we model and analyze the perforn controlled ad-hoc wireless networks: bile hosts are able to change their concentrate on finding schemes for ro tations in these networks. In general find a nl-‘-approximation for any constant E possible strategy for routing a on n mobile hosts. However, we allow ourselves to consider slightly less ge efficient solutions can be found. We first demonstrate that there is a n tributed schemes for handling node-to-no on top of which online route selection and gies can be constructed such that the p class of schemes can be exploited in a near routing permutations in any static power-car network. We then demonstrate to the important case of routin randomly in a Euclidean space, asymptotically optimal for any

Mobile terminal and method for controlling network connection thereof

Abstract: A mobile terminal detects a network formed on a communication media when the mobile terminal is to be connected to said communication media by transmitting control signals to and receiving control signals from the communication media and performs a connection control according to a protocol of a trunk network when the detected network is the trunk network or to a protocol of an ad hoc network when the detected network is the ad hoc network. When the mobile terminal can not detect a network to which the mobile terminal can be connected, the mobile terminal sets a new ad hoc network identifier for forming a new ad hoc network, after determining that the new ad hoc network identifier is not already in use another network.

Optimizations for Location-aided Routing (LAR) in Mobile Ad Hoc Networks

Abstract: Location-Aided Routing (LAR) algorithm is an approach to utilize location information for mobile hosts, with the goal of decreasing routing-related overhead in mobile ad hoc networks. A number of optimizations are possible to improve performance of the basic LAR protocols. This paper mainly focuses how the basic operation of LAR can be improved by applying those optimization schemes.

Source-initiated adaptive routing algorithm (SARA) for autonomous wireless local area networks

Abstract: Conventional routing protocols used in wireline and wireless networks are not designed to operate in an autonomous (or ad hoc) wireless local area network (AWLAN) environment with asymmetric (i.e. unidirectional) links. This paper presents the design of a routing protocol called source-initiated adaptive routing algorithm (SARA), for AWLAN environments that may contain asymmetric links. To allow efficient operation in a symmetric network while ensuring correct operation in asymmetric networks, SARA supports two different modes of protocol operation: one optimized for symmetric networks and the other providing additional capabilities needed for operation in asymmetric networks at a higher cost. The ability of SARA to adapt its mode of operation and optimize its execution for each network environment is one of its major advantages and distinguishes it from existing routing protocols for, wireless networks. Furthermore, within each of its operating modes, SARA supports best-effort as well as policy-based routing.

Resource Discovery in Ad hoc Networks

Abstract: Much of the current research in mobile networking investigates how to support a mobile user within an established infrastructure of routers and servers. Ad hoc networks come into play when no such established infrastructure exits. This paper presents a two-stage protocol to solve the resource discovery problem in ad hoc networks: how hosts discover what resources are available in the network and how they discover how to use the resources. This protocol does not require any established servers or other infrastructure. It only requires routing capabilities in the network.

A medium access protocol for wireless LANs which supports isochronous and asynchronous traffic

Abstract: In this paper we present a medium access control (MAC) protocol for a wireless LAN which is designed to support both isochronous (voice) and asynchronous (data) traffic. The protocol is designed for use in a frequency hopping system and uses a TDMA access protocol to support voice and a CSMA/CA access protocol to support data. A wireless LAN using this protocol can be operated as either an ad-hoc network (in which case only the data service is supported) or as a managed network under the control of a control point or base station (in which case the voice service is also supported).

Efficient routing and quality of service support for ad hoc wireless networks

Abstract: One feature that distinguishes the ad hoc wireless network from traditional wired networks and PCS (personal communication network) is that all hosts in an ad hoc wireless network are allowed to move freely without the need for static access points. This distinct feature, however, presents a great challenge to the design of the routing scheme and the support of multimedia services, since the link quality and the network topology may be fast changing as hosts roam around. In this dissertation, we investigate the behaviors of existing routing algorithms. None of them satisfies the stringent requirements of ad hoc wireless networks. These requirements include: high accuracy, low overhead, scalability in a large network, the possibility of providing QoS routing, etc. Therefore, we propose a new routing approach for ad hoc wireless network: Global State Routing (GSR). Similar to link state routing, GSR maintains a global view of network topology. But unlike link state routing, GSR uses the fisheye technique to keep the control message small, thus reducing the consumption of bandwidth by control overhead. As a result, GSR can be scaled for use in networks with large populations. GSR can also be extended with QoS parameters to perform QoS routing for multimedia applications. In order to validate the results in our investigation, all schemes are simulated and/or implemented in our testbed at UCLA. The implementation of our testbed also involves the creation of several new features in the operating system to provides QoS support in wireless networks, and the creation of new applications which fully utilize this QoS information. With the integration of these features across various layers, we can realize a truly mobile, multimedia, multihop wireless network.

Fully distributed wireless MAC transmission of real-time data

Abstract: As ad hoc wireless networks become more common, the need for real time services on these networks is emerging. However little work has focused on supporting real time requirements in such a demanding environment where the medium of transmission is noisy and protocols must be fully decentralized. Addressing this, we present a MAC protocol, preemptive in nature, that supports the transmission of hard, soft and non real time data. To guarantee stability even in overloaded conditions and still offer support for deadlines, we use splitting protocols. A protocol model is presented and analyzed, showing its performance under a wide range of offered loads with various fractions of real time types. We show that the protocol is easily implemented without making unreasonable hardware demands and so could be used as the basis for building real time services in an ad hoc wireless network.

A Communication Protocol for Clouds of Mobile Robots

Abstract: Mobile robots usually employ dedicated networks to share data and control in an open environment. These networks, called adhoc networks, are multi-hop wireless networks where the mobile devices communicate using a shared, low power, low bandwidth channel. Since the classical routing algorithms of the wired networks cannot be used, new communication and routing protocols are being developed. In this paper we present a new communication protocol that solves data transfer problems, like packet routing, in an ad-hoc network used to control a cloud of robots. This protocol results to be efficient in a situation where a dedicated node, called the coordinator, controls the activity of all the robots, therefore being one of the end-points of any data interchange.