Application‐driven power management for mobile communication

In mobile computing, power is a limited resource. Like other devices, communication devices need to be properly managed to conserve energy. In this paper, we present the design and implementation of an innovative transport level protocol capable of significantly reducing the power usage of the communication device. The protocol achieves power savings by selectively choosing short periods of time to suspend communications and shut down the communication device. It manages the important task of queuing data for future delivery during periods of communication suspension, and decides when to restart communication. We also address the tradeoff between reducing power consumption and reducing delay for incoming data. We present results from experiments using our implementation of the protocol. These experiments measure the energy consumption for three simulated communication patterns as well as three trace‐based communication patterns and compare the effects of different suspension strategies. Our results show up to 83% savings in the energy consumed by the communication. For a high‐end laptop, this can translate to 6–9% savings in the energy consumed by the entire mobile computer. This can represent savings of up to 40% for current hand‐held PCs. The resulting delay introduced is small (0.4–3.1 s depending on the power management level). This revised version was published online in July 2006 with corrections to the Cover Date.     

A pre‐serialization transaction management technique for mobile multidatabases

Rapid advances in hardware and wireless communication technology have made the concept of mobile computing a reality. Thus, evolving database technology needs to address the requirements of the future mobile user. The frequent disconnection and migration of the mobile user violate underlying presumptions about connectivity that exist in wired database systems and introduce new issues that affect transaction management. In this paper, we present the PreSerialization (PS) transaction management technique for the mobile multidatabase environment. This technique addresses disconnection and migration and enforces a range of atomicity and isolation criteria. We also develop an analytical model to compare the performance of the PS technique to that of the Kangaroo model.     

Composable ad hoc location‐based services for heterogeneous mobile clients

This paper introduces a comprehensive architecture that supports adapting a client device's functionality to new services it discovers as it moves into a new environment. Users wish to invoke services – such as controlling the lights, printing locally, gaining access to applicationspecific proxies, or reconfiguring the location of DNS servers – from their mobile devices. But a priori standardization of interfaces and methods for service invocation is infeasible. Thus, the challenge is to develop a new service architecture that supports heterogeneity in client devices and controlled objects while making minimal assumptions about standard interfaces and control protocols. Four capabilities are needed for a comprehensive solution to this problem: (1) allowing device mobility, (2) augmenting controllable objects to make them networkaccessible, (3) building an underlying discovery architecture, and (4) mapping between exported object interfaces and client device controls. We motivate the need for these capabilities by using an example scenario to derive the design requirements for our mobile services architecture. We then present a prototype implementation of elements of the architecture and some example services using it, including controls to audio/visual equipment, extensible mapping, server autoconfiguration, location tracking, and local printer access.     

A low‐complexity multiuser detector for up‐link CDMA QPSK mobile radio communications

This paper deals with a multiuser detector based on a new decorrelating approach for asynchronous uplink DS/CDMA communications in which the QPSK modulation scheme is used in transmission. It is shown here that the receiver proposed is near–far resistant and exhibits a low complexity which allows realtime operation. Performance is expressed in terms of bit error rate (BER) which has been derived by simulations under the assumption of a slowly frequencyselective Rayleigh fading channel.     

Simulation‐based performance evaluation of routing protocols for mobile ad hoc networks

In this paper we evaluate several routing protocols for mobile, wireless, ad hoc networks via packetlevel simulations. The ad hoc networks are multihop wireless networks with dynamically changing network connectivity owing to mobility. The protocol suite includes several 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, endtoend delay, and routing load for a given traffic and mobility model. Both small (30 nodes) and medium sized (60 nodes) networks are used. It is observed that the new generation of ondemand routing protocols use much lower routing load, especially with small number of peertopeer conversations. However, the traditional link state and distance vector protocols provide, in general, better packet delivery and endtoend delay performance.     

A spread‐slotted random‐access protocol with multi‐priority for personal and mobile communication networks carrying integrated traffic

This paper describes and analyzes a medium access protocol for wireless personal communication networks serving integrated traffic. A multipriority mechanism, which is implemented and controlled explicitly by the users and without any involvement from the network is incorporated into the protocol. We examine the proposed protocol under reservation and nonreservation policies and evaluate its performance when handling integrated voice and data traffic. The proposed protocol is suitable to be used in Personal Communication Systems aiming to provide integrated (voice/data) services.     

An evaluation of audio‐centric CMU wearable computers

Carnegie Mellon's Wearable Computers project is defining the future for not only computing technologies but also for the use of computers in daily activities. Fifteen generations of CMU's wearable computers are evolutionary steps in the quest for new ways to improve and augment the integration of information in the mobile environment. The complexity of their architectures has increased by a factor of over 200, and the complexity of the applications has also increased significantly. In this paper, we provide a taxonomy of their capabilities and evaluate the performance of audiocentric CMU wearable computers.     

Adaptive channel assignment for different types of traffic in DS‐CDMA cellular systems

The link capacity of DS‐CDMA cellular systems is limited by the interference contained in the link. This link interference is affected by many environment factors and thus the link capacity varies with the environment. Since link capacity changes with the varying interference and different traffic types mutually interfere with each other, it is difficult to use link capacity efficiently. Static channel assignment (SCA) based on fixed link capacity is inefficient for DS‐CDMA cellular systems. To improve system capacity, channel assignments need to be adapted to variations in interference. In this paper, we propose an adaptive channel assignment (ACA) for different types of traffic. The proposed ACA is based on the reverse link power received at the base station and is adaptable to dynamically varying environments. It consists of two schemes: nonprioritized and prioritized. In the nonprioritized scheme, there is no difference in channel assignments between calls. In the prioritized scheme, however, the number of nonpriority calls acceptable is limited. In both schemes, a channel is assigned if the link power after assigning the channel is less than the power allowed in the link. The performance is evaluated in terms of link capacity and service grade. Utilizing the proposed algorithm yields more link capacity than using SCA in such environment changes as nonhomogeneous traffic load or varying path loss. Service grade is also improved by properly limiting the number of nonpriority channels. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mobility model and performance analysis for zone‐based registration in CDMA mobile communication system

In this paper, we describe a mobility model and analysis for zone-based registration in the CDMA mobile communication system. We first propose a simple and proper mobility function for single zone-based registration. We establish the circumstances of multiple zone-based registration, which is based on the mobility function of single zone-based registration, and perform computer simulations for the circumstances. Using the simulation results, we obtain the optimal number of zones, N, that minimizes signaling traffic on radio channels. Results show that, in most cases, N is 2. We also show that multiple zone-based registration has lower signaling traffic on radio channels than single zone-based registration, and zone‐based registration must be implemented as multiple zone‐based registration. This revised version was published online in August 2006 with corrections to the Cover Date.     

Design and analysis of low‐power access protocols for wireless and mobile ATM networks

This paper describes the design and analysis of a low‐power medium access control (MAC) protocol for wireless/mobile ATM networks. The protocol – denoted EC‐MAC (energy conserving medium access control) – is designed to support different traffic types with quality‐of‐service (QoS) provisions. The network is based on the infrastructure model where a base station (BS) serves all the mobiles currently in its cell. A reservation‐based approach is proposed, with appropriate scheduling of the requests from the mobiles. This strategy is utilized to accomplish the dual goals of reduced energy consumption and quality of service provision over wireless links. A priority round robin with dynamic reservation update and error compensation scheduling algorithm is used to schedule the transmission requests of the mobiles. Discrete‐event simulation has been used to study the performance of the protocol. A comparison of energy consumption of the EC‐MAC to a number of other protocols is provided. This comparison indicates the EC‐MAC has, in general, better energy consumption characteristics. Performance analysis of the proposed protocol with respect to different quality‐of‐service parameters using video, audio and data traffic models is provided. This revised version was published online in August 2006 with corrections to the Cover Date.     

A center‐controlled dynamic rerouting scheme for fast and reliable handover in mobile ATM networks

This paper proposes a scheme for fast and reliable handover that uses dynamic rerouting controlled by a call setup control station (CCS) operating in mobile asynchronous transfer mode (ATM) networks. The CCS selects appropriate rerouted path and crossover switch (COS), and remotely controls the new path's setup. This omits crossover switch discovery process, and makes fast handover possible. The CCS can select the appropriate rerouted path because it directly and with little delay collects information about the state of links such as traffic loads, quality-of-service (QoS) parameters, and disconnection or restoration of links advertised from every ATM switch in its domain. This reduces blocking and congestion, and makes reliable handover possible. The CCS accepts a handover request message for either backward or forward handover, and can remotely control the new path's setup in the same manner for either handover. The scheme provides forward handover when the radio propagation conditions deteriorate unpredictably. This paper also shows sequences of call origination, connection pre-establishment, and route-change in our proposed scheme, and illustrates operation of the CCS and the ATM switches. This revised version was published online in June 2006 with corrections to the Cover Date.     

Adaptive Threshold Median Filter for Multiple-Impulse Noise

Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. In this paper, a new adaptive median filter is proposed to handle those images corrupted not only by single layer noise. The adaptive threshold median filter （ATMF） has been developed by combining the adaptive median filter （AMF） and two dynamic thresholds. Because of the dynamic threshold being used, the ATMF is able to balance the removal of the multiple-impulse noise and the quality of image. Comparison of the proposed method with traditional median filters is provided. Some visual examples are given to demonstrate the performance of the proposed filter.     

An Adaptive Clustering Algorithm for Intrusion Detection

1 IntroductionBefore data mining techniques are introduced into net-workintrusion detection,intrusion detection was heavily de-pended on a manually maintained knowledge base which con-tained signature of all known attacks.Features of monitorednetworktraff…     

Weighted cooperative routing for wireless mobile Ad-hoc network

A novel weighted cooperative routing algorithm (WCRA) is proposed in this article, which was on the basis of a weighted metric with maximal remaining energy (MRE) of the relays and the maximal received SNR (MRS) of the nodes. Moreover, a cooperative routing protocol was implemented on the basis of WCRA. Then simulation is done on network simulation (NS-2) platform to compare the performances of MRS, MRE and WCRA with that of noncooperative destination-sequenced destination-sequenced distance-vector (DSDV) protocol. The simulative results show that WCRA obtains a performance tradeoff between MRE and MRS in terms of delivery ratio and network lifetime, which can effectively improve the network lifetime at an acceptable loss of delivery ratio.     

A new approach to the design and analysis of peer‐to‐peer mobile networks

This paper introduces a new model and methodological approach for dealing with the probabilistic nature of mobile networks based on the theory of random graphs. Probabilistic dependence between the random links prevents the direct application of the theory of random graphs to communication networks. The new model, termed Random Network Model, generalizes conventional random graph models to allow for the inclusion of link dependencies in a mobile network. The new Random Network Model is obtained through the superposition of Kolmogorov complexity and random graph theory, making in this way random graph theory applicable to mobile networks. To the best of the authors' knowledge, it is the first application of random graphs to the field of mobile networks and a first general modeling framework for dealing with adhoc network mobility. The application of this methodology makes it possible to derive results with proven properties. The theory is demonstrated by addressing the issue of the establishment of a connected virtual backbone among mobile clusterheads in a peertopeer mobile wireless network. Using the Random Network Model, we show that it is possible to construct a randomized distributed algorithm which provides connectivity with high probability, requiring exponentially fewer connections (peertopeer logical links) per clusterhead than the number of connections needed for an algorithm with a worst case deterministic guarantee.     

Location‐Aided Routing (LAR) in mobile ad hoc networks

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 paper 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. By using location information, the proposed Location‐Aided Routing (LAR) protocols limit the search for a new route to a smaller “request zone” of the ad hoc network. This results in a significant reduction in the number of routing messages. We present two algorithms to determine the request zone, and also suggest potential optimizations to our algorithms. This revised version was published online in July 2006 with corrections to the Cover Date.     

ARMS-EGR—Adaptive ranking and mobile sink-enabled energy-efficient geographic routing protocol in flying ad hoc networks

Unmanned aerial vehicles (UAVs) have become widespread because of their involvement in a variety of applications. The task of designing the energy-efficient routing between UAVs has been considered a matter of great interest due to the inherent challenges of controlling the dynamics exhibited by UAVs. Energy limitations are considered the main limitations of UAVs. This research paper proposes a novel routing protocol, adaptive ranking and mobile sink (MS)-enabled energy-efficient geographic routing (ARMS-EGR) for flying ad hoc networks. In ARMS-EGR, the whole network is partitioned into cells. The cell contains cell members (CM) and cell heads (CHs). The CH works as a cluster head. Additionally, two MSs have been used to collect data captured by CM. Multihop communication on the network leads to an increase in traffic and consumes the energy of the UAVs located near the base station (BS). MSs are used for power distribution and load balancing across the network. Adaptive ranking of forwarder UAVs and CHs is performed during intracell and intercell multihop communication, respectively, using adaptive ranking. A cell with one-hop communication can directly send packets to the MS, but the ARMS-EGR routing protocol has been proposed for multihop communication. The proposed approach is simulated in NS-2.35 software. The results show that end-to-end latency and power consumption during packet transmission are greatly minimized. ARMS-EGR also demonstrates improvements in message success rates, number of alive nodes, and packet delivery ratio, making ARMS-EGR particularly suitable for flying ad hoc networks (FANETs).     

Channel Adaptive Shortest Path Routing for Ad Hoc Networks

1　IntroductionAdhocnetworksareformedwithoutrequiringthepreexistinginfrastructureorcentralizedadminis tration ,incontrasttocellularnetworks.Asidefromtheoriginalmilitaryapplication ,ithasapplicationinpublicsafetyandcommercialareas,butadaptiveprotocolsarerequiredinorderforthemtodoso .Twoimportantcharacteristicsofacommunicationlinkinadhocnetworksareitsunreliabilityanditsvariability .Thelinksinsuchanetworkareunreli ablebecauseoffading ,interference,noise,andper hapsthefailureofthetransmittingorrec…     

Providing reliable and fault tolerant broadcast delivery in mobile ad‐hoc networks

Mobile adhoc networks are making a new class of mobile applications feasible. They benefit from the fast deployment and reconfiguration of the networks, are mainly characterized by the need to support manytomany interaction schema within groups of cooperating mobile hosts and are likely to use replication of data objects to achieve performances and high data availability. This strong group orientation requires specialized solutions that combine adaptation to the fully mobile environment and provide the adequate level of fault tolerance. In this paper, we present the reliable broadcast protocol that has been purposely designed for mobile adhoc networks. The reliable broadcast service ensures that all the hosts in the network deliver the same set of messages to the upper layer. It represents the building block to obtain higher broadcast and multicast services with stronger guarantees and is an efficient and reliable alternative to flooding. The protocol is constructed on top of the wireless MAC protocol, which in turn sits over the clustering protocol. It provides an exactly once message delivery semantics and tolerates communication failures and host mobility. Temporary disconnections and network partitions are also tolerated under the assumption that they are eventually repaired, as specified by a Liveness property. The termination of the protocol is proved and complexity and performance analyses are also provided.