A cooperative multihop radio resource allocation in next generation networks

With the objectives of improving 3G networks coverage by using relaying nodes, a game theoretic approach to radio resource allocation for the downlink capacity is introduced. One of the basic issues not examined in the literature is the importance of fair resource sharing among mobile nodes located along a multihop link. We describe a novel technique for providing a resource allocation mechanism in a multihop relaying network. The resource allocation problem is formulated as a cooperative game using Nash Bargaining Solution (NBS), which allows mobile nodes to fairly share a downlink bandwidth among themselves. Sharing of the downlink capacity between multiple nodes using a noncooperative approach is inefficient when the radio resource is scarce. If upstream nodes manipulate their location at the head of the multihop link to exploit the downlink capacity, downstream nodes will suffer disproportionately. The undesirable properties can be avoided by means of a cooperative agreement in which all nodes share the radio resources equally, where downstream nodes are allowed to pay compensation to prevent upstream nodes from exploiting the downlink capacity and encourage them to cooperate. © 2005 IEEE

Pc1-Pc2 waves and energetic particle precipitation during and after magnetic storms: superposed epoch analysis and case studies

Magnetic pulsations in the Pc1-Pc2 frequency range (0.1-5 Hz) are often observed on the ground and in the Earth's magnetosphere during the aftermath of geomagnetic storms. Numerous studies have suggested that they may play a role in reducing the fluxes of energetic ions in the ring current; more recent studies suggest they may interact parasitically with radiation belt electrons as well. We report here on observations during 2005 from search coil magnetometers and riometers installed at three Antarctic stations, Halley (-61.84 degrees magnetic latitude, MLAT), South Pole (-74.18 degrees MLAT), and McMurdo (-79.96 degrees MLAT), and from energetic ion detectors on the NOAA Polar-orbiting Operational Environment Satellites (POES). A superposed epoch analysis based on 13 magnetic storms between April and September 2005 as well as case studies confirm several earlier studies that show that narrowband Pc1-Pc2 waves are rarely if ever observed on the ground during the main and early recovery phases of magnetic storms. However, intense broadband Pi1-Pi2 ULF noise, accompanied by strong riometer absorption signatures, does occur during these times. As storm recovery progresses, the occurrence of Pc1-Pc2 waves increases, at first in the daytime and especially afternoon sectors but at essentially all local times later in the recovery phase (typically by days 3 or 4). During the early storm recovery phase the propagation of Pc1-Pc2 waves through the ionospheric waveguide to higher latitudes was more severely attenuated. These observations are consistent with suggestions that Pc1-Pc2 waves occurring during the early recovery phase of magnetic storms are generated in association with plasmaspheric plumes in the noon-to-dusk sector, and these observations provide additional evidence that the propagation of waves to ground stations is inhibited during the early phases of such storms. Analysis of 30- to 250-keV proton data from four POES satellites during the 24-27 August and 18-19 July 2005 storm intervals showed that the location of the inner edge of the ring current matched well with the plasmapause model of O'Brien and Moldwin (2003). However, the POES data showed no evidence of the consequences of electromagnetic ion cyclotron waves (localized proton precipitation) during main and early recovery phase. During later stages of the recovery phase, when such precipitation was observed, it was coincident with intense wave events at Halley, and it occurred at L shells near or up to 1 RE outside the modeled plasmapause but well equatorward of the isotropy boundary

An evaluation of three DoE-guided meta-heuristic-based solution methods for a three-echelon sustainable distribution network

This article evaluates the efficiency of three meta-heuristic optimiser (viz. MOGA-II, MOPSO and NSGA-II)-based solution methods for designing a sustainable three-echelon distribution network. The distribution network employs a bi-objective location-routing model. Due to the mathematically NP-hard nature of the model a multi-disciplinary optimisation commercial platform, modeFRONTIER®, is adopted to utilise the solution methods. The proposed Design of Experiment (DoE)-guided solution methods are of two phased that solve the NP-hard model to attain minimal total costs and total CO2 emission from transportation. Convergence of the optimisers are tested and compared. Ranking of the realistic results are examined using Pareto frontiers and the Technique for Order Preference by Similarity to Ideal Solution approach, followed by determination of the optimal transportation routes. A case of an Irish dairy processing industry’s three-echelon logistics network is considered to validate the solution methods. The results obtained through the proposed methods provide information on open/closed distribution centres (DCs), vehicle routing patterns connecting plants to DCs, open DCs to retailers and retailers to retailers, and number of trucks required in each route to transport the products. It is found that the DoE-guided NSGA-II optimiser based solution is more efficient when compared with the DoE-guided MOGA-II and MOPSO optimiser based solution methods in solving the bi-objective NP-hard three-echelon sustainable model. This efficient solution method enable managers to structure the physical distribution network on the demand side of a logistics network, minimising total cost and total CO2 emission from transportation while satisfying all operational constraints

Future military mobile radio communication systems from electronic warfare perspective

Abstract Detection devices are becoming more wideband, faster scanning and their signal processing capabilities are increasing. In addition, sophisticated jamming devices have become rather powerful. As a consequence, threats to military radio communications have increased such that it is about time to discuss what features future military radio systems should have in order to battle against these increased menaces. This paper fills this gap by considering this problem from the point of view of electronic warfare physics. The result is a set of features that would help in the engagement. Furthermore, it discusses what effects these features have for radio system design. The proposed features add new properties, compared with legacy radios, that require new control functionalities that have to cooperate with old ones as well as together and also add radio hardware. Therefore, corresponding research problems will not be easily solved

A cooperative multihop radio resource allocation in next generation networks

With the objectives of improving 3G networks coverage by using relaying nodes, a game theoretic approach to radio resource allocation for the downlink capacity is introduced. One of the basic issues not examined in the literature is the importance of fair resource sharing among mobile nodes located along a multihop link. We describe a novel technique for providing a resource allocation mechanism in a multihop relaying network. The resource allocation problem is formulated as a cooperative game using Nash Bargaining Solution (NBS), which allows mobile nodes to fairly share a downlink bandwidth among themselves. Sharing of the downlink capacity between multiple nodes using a noncooperative approach is inefficient when the radio resource is scarce. If upstream nodes manipulate their location at the head of the multihop link to exploit the downlink capacity, downstream nodes will suffer disproportionately. The undesirable properties can be avoided by means of a cooperative agreement in which all nodes share the radio resources equally, where downstream nodes are allowed to pay compensation to prevent upstream nodes from exploiting the downlink capacity and encourage them to cooperate. © 2005 IEEE

Internetwork time synchronization of mobile Ad Hoc networks

Abstract Several time synchronous ad hoc networks may operate in the same geographical area. Although network time synchronization within an individual network has been widely discussed, internetwork time synchronization relying on time sources the networks carry has not been addressed. Therefore, this paper proposes an internetwork time synchronization procedure that allows to use one network as a time source and share its time, like a global navigation satellite system time, to other networks. The internetwork time synchronization procedure runs in gateway nodes that could be a member in several networks, and it collaborates with the individual network time synchronization algorithms that operate at the network level. Consequently, the paper proposes a generic, robust hybrid network time synchronization protocol and analyses its performance using a sensible metric called a mutual consensus. It is shown that the common time is achieved with a limited variance in the networks that operate in the master-slave, distributed or hybrid mode. Provided numerical examples illustrate the behavior of the algorithm and confirm the theoretical findings

A cooperative multihop radio resource allocation in next generation networks

With the objectives of improving 3G networks coverage by using relaying nodes, a game theoretic approach to radio resource allocation for the downlink capacity is introduced. One of the basic issues not examined in the literature is the importance of fair resource sharing among mobile nodes located along a multihop link. We describe a novel technique for providing a resource allocation mechanism in a multihop relaying network. The resource allocation problem is formulated as a cooperative game using Nash Bargaining Solution (NBS), which allows mobile nodes to fairly share a downlink bandwidth among themselves. Sharing of the downlink capacity between multiple nodes using a noncooperative approach is inefficient when the radio resource is scarce. If upstream nodes manipulate their location at the head of the multihop link to exploit the downlink capacity, downstream nodes will suffer disproportionately. The undesirable properties can be avoided by means of a cooperative agreement in which all nodes share the radio resources equally, where downstream nodes are allowed to pay compensation to prevent upstream nodes from exploiting the downlink capacity and encourage them to cooperate. © 2005 IEEE

Estimating relativistic electron pitch angle scattering rates using properties of the electromagnetic ion cyclotron wave spectrum

An EMIC wave event observed by the CRRES spacecraft during an active period on 11 August 1991 was studied in order to estimate electron minimum interaction kinetic energy Emin and using quasilinear theory, to calculate the resonant scattering rate Dαα. The wave packet semibandwidth δω/2π full-width half maximum ranged from 0.06 Hz to 0.27 Hz. Resonant scattering was assumed to occur over the frequency interval ωm - δω to ωm + δω. Assuming typical stormtime ion concentrations, the use of realistic wave spectral properties when compared to only using the central wave frequency ωm results in 3 to 4 times as many wave packets that are able to interact with relativistic electrons below ∼2 MeV. Values of D αα associated with two of the wave packets, where E min falls to within the 1-2 MeV energy range, were comparable to the limit of strong diffusion suggesting enhanced electron precipitation. CRRES observed an ∼1 order of magnitude decrease in the 1-2 MeV electron flux levels during the EMIC wave interval. It is suggested that this flux decrease was due to EMIC waves pitch angle scattering the relativistic electrons. The EMIC waves were observed near the start of the main phase of a geomagnetic storm. This study strengthens the suggestion that relativistic electron scattering by EMIC waves can compete with the Dst effect as a mechanism of decreasing relativistic electron fluxes from the outer zone during magnetic storms