Showing papers on "Optimized Link State Routing Protocol published in 1998"
25 Oct 1998
TL;DR: The results of a derailed packet-levelsimulationcomparing fourmulti-hopwirelessad hoc networkroutingprotocols, which cover a range of designchoices: DSDV,TORA, DSR and AODV are presented.
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.
5,147 citations
25 Oct 1998
TL;DR: An approach to utilize location information (for instance, obtained using the global positioning system) to improve performance of routing protocols for ad hoc networks is suggested.
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.
2,854 citations
25 Oct 1998
TL;DR: In this article, the authors present a case for using new power-aware metn.cs for determining routes in wireless ad hoc networks and show that using these new metrics ensures that the mean time to node failure is increased si~cantly.
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.
1,885 citations
01 Jul 1998
TL;DR: A new multiaccess protocol based on the original MACA protocol with the adition of a separate signalling channel that conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets.
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.
1,257 citations
01 Oct 1998
TL;DR: This paper studies the performance of route query control mechanisms for the recently proposed Zone Routing Protocol (ZRP) for ad-hoc networks and demonstrates how certain combinations of these techniques can be applied to single channel or multiple channel ad-Hoc networks to improve both the delay and control traffic performance of the ZRP.
Abstract: In this paper, we study the performance of route query control mechanisms for the recently proposed 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 has the potential to be more efficient in the generation of control traffic than traditional routing schemes. However, without proper query control techniques, the ZRP can actually produce more traffic than standard flooding protocols.Our proposed query control schemes exploit the structure of the routing zone to provide enhanced detection (Query Detection (QD1/QD2)), termination (Loop-back Termination (LT), Early Termination (ET)) and prevention (Selective Bordercasting (SBC)) of overlapping queries. We demonstrate how certain combinations of these techniques can be applied to single channel or multiple channel ad-hoc networks to improve both the delay and control traffic performance of the ZRP. Our query control mechanisms allow the ZRP to provide routes to all accessible network nodes with only a fraction of the control traffic generated by purely proactive distance vector and purely reactive flooding schemes, and with a response time as low as 10% of a flooding route query delay.
514 citations
07 Jun 1998
TL;DR: A new scheme especially designed for routing in an ad-hoc wireless environments, called "global state routing" (GSR), where nodes exchange vectors of link states among their neighbors during routing information exchange, which provides a better solution than existing approaches in a truly mobile, ad-Hoc environment.
Abstract: In an ad-hoc environment with no wired communication infrastructure, it is necessary that mobile hosts operate as routers in order to maintain the information about connectivity. However with the presence of high mobility and low signal/interference ratio (SIR), traditional routing schemes for wired networks are not appropriate, as they either lack the ability to quickly reflect the changing topology, or may cause excessive overhead, which degrades network performance. Considering these restrictions, we propose a new scheme especially designed for routing in an ad-hoc wireless environments. We call this scheme "global state routing" (GSR), where nodes exchange vectors of link states among their neighbors during routing information exchange. Based on the link state vectors, nodes maintain a global knowledge of the network topology and optimize their routing decisions locally. The performance of the algorithm, studied in this paper through a series of simulations, reveals that this scheme provides a better solution than existing approaches in a truly mobile, ad-hoc environment.
478 citations
Patent•
24 Aug 1998TL;DR: In this article, two network communication protocols, one for routing and one for mobility management, are presented that are particularly suited for use with ad-hoc networks, and the reactive procedure is limited during route discovery to queries of only those nodes located on the periphery of routing zones.
Abstract: Two network communication protocols, one for routing and one for mobility management, are presented that are particularly suited for use with ad-hoc networks. The routing protocol is a proactive-reactive hybrid routing protocol that limits the scope of the proactive procedure to the node's local neighborhood. Routing zones are defined for each node that include nodes whose distance from the subject node in hops is at most some predefined number, referred to as the zone radius. Each node is required to know the topology of the network within its routing zone only. The reactive procedure is limited during route discovery to queries of only those nodes located on the periphery of routing zones. In this manner, the queries hop across nodes in distances of zone radius, thus limiting the scope of the reactive procedure. The zone radius is preferably adjustable to accommodate different and differing network topologies and network operational conditions in the most efficient manner. The mobility management protocol relies on some network nodes assuming the mobility management function. In this scheme, each network node is “associated” with one or more mobility management nodes. The mobility management nodes form a virtual network which is embedded within the actual ad-hoc network. Each mobility management node knows the location of all nodes within its zone, and communicates this information to any other mobility management node that requests it.
477 citations
16 Dec 1998
TL;DR: The main result is this: if n nodes are located randomly, uniformly i.i.d., in a disc of unit area in /spl Rfr//sup 2/ and each node transmits at a power level so as to cover an area of /spl pi/r/Sup 2/=(log n + c(n))/n, then the resulting network is asymptotically connected with probability one as the number of nodes in the network goes to infinity.
Abstract: In wireless data networks the range of each transmitter, and thus its power level, needs to be high enough to reach the intended receivers, while being low enough to avoid generating interference for other receivers on the same channel. If the nodes in the network are assumed to cooperate, perhaps in a distributed and decentralized fashion, in routing each others' packets, as is the case in ad hoc wireless networks, then each node should transmit with just enough power to guarantee connectivity of the overall network. Towards this end, we determine the critical power at which a node in the network needs to transmit in order to ensure that the network is connected with probability one as the number of nodes in the network goes to infinity. Our main result is this: if n nodes are located randomly, uniformly i.i.d., in a disc of unit area in /spl Rfr//sup 2/ and each node transmits at a power level so as to cover an area of /spl pi/r/sup 2/=(log n + c(n))/n, then the resulting network is asymptotically connected with probability one if and only if c(n)/spl rarr/+/spl infin/.
352 citations
12 Oct 1998
TL;DR: 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.
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.
332 citations
11 Oct 1998
TL;DR: The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network and enables an efficient call admission control.
Abstract: The emergence of nomadic applications have generated a lot of interest in wireless network infrastructures which support multimedia services. We propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e.g. ATM or the Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy the bandwidth requirement for the QoS constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance.
TL;DR: This work introduces a self organizing network structure called a spine and proposes a spine-based routing infrastructure for routing in ad hoc networks and proposes two spine routing algorithms: Optimal Spine Routing (OSR), which uses full and up-to-date knowledge of the network topology, and (b) Partial-knowledge SpineRouting (PSR, which uses partialknowledge of thenetwork topology.
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.
05 Oct 1998
TL;DR: This paper motivates the need for new multicast routing protocols aimed specifically at fully-mobile (ad hoc) networks, and believes that, due to their inherent broadcast capability, wireless networks are well-suited for multicast communication.
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.
29 Mar 1998
TL;DR: Simulation results are presented showing that the ALVA outperforms the OSPF in terms of communication and storage overhead.
Abstract: An area-based link-vector algorithm (ALVA) is introduced for the distributed maintenance of routing information in very large internetworks. According to ALVA, destinations in an internetwork are aggregated in areas in multiple levels of hierarchy. Routers maintain a database that contains a subset of the topology at each level of the hierarchy. This subset corresponds to those links used in preferred paths to reach destinations (nodes inside the same immediate area or remote areas). The ALVA is the first hierarchical routing algorithm based on link-state information that does not require complete topology information at each level in the hierarchy. The correctness of the ALVA is verified. Simulation results are presented showing that the ALVA outperforms the OSPF in terms of communication and storage overhead.
30 Jun 1998
TL;DR: This work proposes a self-organizing, dynamic infrastructure called a spine for efficient routing in ad hoc networks that encompasses a range of knowledge at each spine node, and identifies the trade-offs involved for routing at different points in this range.
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.
05 Oct 1998
TL;DR: This draft presents CEDAR, a Core-Extraction Distributed Ad hoc Routing algorithm for QoS routing in ad hoc network environments, and a QoS route computation algorithm that is executed at the core nodes using only locally available state.
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
07 Jun 1998
TL;DR: It is demonstrated that ZRP significantly reduces the delay and the amount of routing overhead by providing each node with continuous updates of its local neighborhood (routing zone) topology only.
Abstract: In this paper, we investigate the performance of a novel routing protocol, the zone routing protocol (ZRP), that was introduced in Haas (1997). The protocol is targeted at a special class of ad-hoc networks, which we refer to as the reconfigurable wireless networks (RWNs). RWNs are distinguished from other ad-hoc networks by their increased node mobility, larger number of nodes, and wider network span. We demonstrate that ZRP significantly reduces the delay and the amount of routing overhead by providing each node with continuous updates of its local neighborhood (routing zone) topology only. The structure of the routing zone is exploited to efficiently acquire routes on demand for destinations that lie beyond a node's routing zone. By adjusting a single parameter-the size of the routing zone-the ZRP can adapt to a variety of network operational conditions.
18 May 1998
TL;DR: This work presents a generalized approach called "k-hop cluster-based dynamic source routing", which is simple and can take actions on the host movements quickly and consider the overall channel utilization as well as host mobility.
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.
01 Jan 1998
TL;DR: 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.
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.
01 Jun 1998
TL;DR: This work model and analyze the perforn controlled ad-hoc wireless networks and demonstrates to the important case of routin randomly in a Euclidean space, asymptotically optimal for any route selection or routing permutations.
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
Patent•
NEC1
TL;DR: In this paper, 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 ad hoc network.
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.
23 Nov 1998
TL;DR: In this paper, a number of optimizations are proposed to improve the performance of the basic location-aided routing (LAR) protocol in mobile ad hoc networks, focusing on how the basic operation of LAR can be improved.
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.
11 Oct 1998
TL;DR: The design of a routing protocol called source-initiated adaptive routing algorithm (SARA), for AWLAN environments that may contain asymmetric links, 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.
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.
01 Aug 1998
TL;DR: 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.
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.
07 Jun 1998
TL;DR: The two schemes have been contrasted in the case of wireless mobile hosts linked by means of a wired backbone and the simulation results show that the performance in terms of packet delay and loss as well as the overhead of control traffic largely depend on the offered traffic pattern.
Abstract: Great interest in recent years has been devoted to mobile communications, as well as to Internet and IP based networks. The most promising protocol proposals for the handling of host mobility in IP networks are Mobile IP (MIP) and Route Optimization Mobile IP (ROMIP). The two schemes have been contrasted in the case of wireless mobile hosts linked by means of a wired backbone. The simulation results show that the performance in terms of packet delay and loss as well as the overhead of control traffic largely depend on the offered traffic pattern.
Journal Article•
TL;DR: The study shows that HDRP provides a new available approach torouting decision for DLCN and a method for estimating the link error probability and the relative routing policy that are based on the learning automation theory are presented.
Abstract: This paper presents a hierarchical dynamic routing protocol (HDRP)based on the discrete dynamic programming principle. The proposed protocol canadapt to dynamic and large computer networks (DLCN) with clustering topology.The procedures for realizing routing update and routing decision are given. Theproof of correctness and complexity analysis of the protocol are also made. Theperformance measures including throughput and average message delay are evaluatedusing simulation. Meanwhile,a method for estimating the link error probability andthe relative routing policy that are based on the learning automation theory are alsopresented. The study shows that HDRP provides a new available approach torouting decision for DLCN.
18 May 1998
TL;DR: By properly seizing the zone radius, the routing overhead can be lower (sometimes much lower) than the overhead of both reactive and proactive schemes.
Abstract: Reconfigurable wireless networks (RWNs) are a special class of ad-hoc networks that are characterized by: large geographical coverage, wide range of nodal mobility, and large nodal density. Recently, a new routing protocol for this type of networks was proposed and coined the zone routing protocol (ZRP). The main feature of the ZRP protocol is its dynamic behavior-the operation of the scheme is governed by a single parameter, the zone radius, which adjusts the scheme's behavior from purely reactive to proactive routing. We study the performance of the scheme, evaluating the average number of control messages required to discover a route within the network. Our results show that by properly seizing the zone radius, the routing overhead can be lower (sometimes much lower) than the overhead of both reactive and proactive schemes.
08 Nov 1998
TL;DR: In this paper, a bandwidth routing algorithm for multimedia support in a multihop wireless network is proposed, which can be interconnected to wired networks (e.g. ATM or Internet) or stand alone.
Abstract: The emergence of nomadic applications have generated a lot of interest in wireless network infrastructures which support multimedia services. We propose a bandwidth routing algorithm for multimedia support in a multihop wireless network. This network can be interconnected to wired networks (e.g. ATM or Internet) or stand alone. Our bandwidth routing includes bandwidth calculation and reservation schemes. Under such a routing algorithm, we can derive a route to satisfy the bandwidth requirement for the QoS constraint. At a source node, the bandwidth information can be used to decide to accept a new call or not immediately. This is specially important to carry out a fast handoff when interconnecting to an ATM backbone infrastructure. It enables an efficient call admission control. The simulation results show that the bandwidth routing algorithm is very useful in extending the ATM virtual circuit service to the wireless network. Different types of QoS traffic can be integrated in such a dynamic radio network with high performance.
01 Jan 1998
TL;DR: This dissertation proposes 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 and uses the fisheye technique to keep the control message small, thus reducing the consumption of bandwidth by control overhead.
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.
03 Jun 1998
TL;DR: A MAC protocol, preemptive in nature, that supports the transmission of hard, soft and non real time data, and 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.
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.