Device-to-Device communications have the great potential to bring significant performance boost to the conventional heterogeneous network by reusing cellular resources. In cellular networks, Device-to-Device communication is defined as two user equipments in a close range communicating directly with each other without going through the base station, thus offloading cellular traffic from cellular networks. In addition to improve network spectral efficiency, D2D communication can also improve energy efficiency and user experience. However, the co-existence of D2D communication on the same spectrum with cellular users can cause severe interference to the primary cellular users. Thus the performance of cellular users must be assured when supporting underlay D2D users. In this work, we have investigated cross-layer optimization, resource allocation and interference management schemes to improve user experience, system spectral efficiency and energy efficiency for D2D communication underlaying heterogeneous networks. By exploiting frequency reuse and multi-user diversity, this research work aims to design wireless system level algorithms to utilize the spectrum and energy resources efficiently in the next generation wireless heterogeneous network.

The focus of this thesis is on the resource allocation problems in wireless sensor and cooperative networks. Typically, wireless sensor networks operate with limited energy and bandwidth are often required to meet some specified Quality-of-Service (QoS) constraints. The ultimate objective for the majority of the problems considered in this thesis is to save battery energy and maximize the network lifetime. / In the first part of this thesis, we employ complex mathematical models to emulate a variety of power drains in wireless sensor nodes. In the first instance, we address a lifetime optimization problem of a wireless TDMA/CDMA sensor network for joint transmit power and rate allocations. The effect of fast fading is captured by including rate outage and link outage constraints on each link. After that, a single-hop wireless sensor network is deployed for a certain application - to estimate a Gaussian source within a pre-specified distortion threshold. In this part, we consider lifetime maximization, in different multiple access protocols such as TDMA, an interference limited non-orthogonal multiple access (NOMA) and an idealized Gaussian multiple access channel. This problem is further studied in a multi-hop scenario where sensing and receiving powers are also included in addition to transmission power. Finally, we investigate a balancing problem between the source coding and transmission power for video wireless sensor systems where the sensor node is required to send the collected video clips, through wireless media, to a base station within a corresponding distortion threshold. All these energy saving and lifetime optimization problems in sensor networks can be formulated via nonlinear nonconvex optimization problems, which are generally hard to solve. However, with favourable variable substitution and reasonable approximation, most of these problems are shown to be convex. The only exception is the Gaussian source esitmation problem in NOMA scenario for which we provide a simple successive convex approximation based algorithm for the NOMA case that converges fast to a suboptimal solution. / In the second part of the thesis, we propose an optimal power allocation scheme with a K-block coding delay constraint on data transmission using a three node cooperative relay network assuming a block fading channel model. Channel information is fed back to the transmitter only in a causal fashion, so that the optimal power allocation strategy is only based on the current and past channel gains. We consider the two simplest schemes for information transmission using a three node (a source, a relay and a destination) relay network, namely the amplify and forward (AF) and decode and forward (DF) protocols. We use the dynamic programming methodology to solve the (K-block delay constrained) expected capacity maximization problem and the outage probability minimization problem with a short term sum power (total transmission power of the source and the relay) constraint. / The main contribution of the thesis is a comprehensive suite of power minimization and lifetime maximization methods that can be used in wireless sensor networks. We present several such applications and extensive numerical examples at the end of each chapter.

<p>Much work has been done in simulating traditional cellular networks. But with the incoming of ad-hoc network technology, the next generation networks will employ hybrid network architectures using both cellular and ad-hoc networking concepts. </p><p>We investigate how to create a simulator being able to simulate a hybrid wireless network. This involves setting up a cellular network and an ad-hoc network respectively. However, the most important thing is how to integrate them seamlessly. </p><p>Fortunately, there has already been a simulator called SIMRA which simulates a UMTS cellular network. Therefore, this thesis work is greatly simplified as how to extend and improve SIMRA to implement a simulator for hybrid wireless network. We selected J-sim as the developing platform for our simulator and our development was greatly based on the wireless package provided by the latest version of J-sim. </p><p>To evaluate the new simulator, different resource allocation algorithms were run against it and the results were compared to those generated by earlier extensions to SIMRA under the same simulation settings. It showed that the resource allocation algorithms behaved similarly under the hybrid wireless network environment. Nevertheless, there are some discrepancies in behaviors of algorithms used for evaluation that still need to be studied.</p>

<p>The use of relays is seen as a promising way to extend cell coverage and increase rates in LTE Advanced networks. Instead of increasing the number of base stations (BS), relays with lower cost could provide similar gains. A relay will have a wireless link to the closest BS as only connection to the core network and will cover areas close to the cell edge or other areas with limited rates.</p><p>Performing transmissions in several hops (BS-relay & relay-user) requires more radio resources than using direct transmission. This thesis studies how the available radio resources should be allocated between relays and users in order to maximize throughput and/or fairness. Time and frequency multiplexed backhaul is investigated under a full buffer traffic assumption. It is shown that the system will be backhaul limited and that the two ways of multiplexing will perform equally when maximising throughput and/or fairness. The analysis results in a set of throughput/fairness suboptimal solutions, dependant on how many relays are used per cell. The results are verified by simulations, which also show the limiting effects on throughput caused by interference between relays.</p><p>It is also analysed how the resource allocation should be done given non-fullbuffer traffic. A resource allocation that minimises packet delay given a certain number of relays per cell is presented. The analysis is based on queuing theory.</p><p>Finally some different schedulers and their suitability for relay networks are discussed. Simulation results are shown, comparing the throughput and fairness of Round Robin, Weighted Round Robin, Proportional Fairness and Weighted Proportional Fairness schemes. It is shown that allocating the resource among the relays according to the number of users served by the relays improves the fairness.</p>

<p>The new mobile standard Long Term Evolution delivers high data rates, small delay and a more efficiently utilized RF spectrum. A solution to maintain this performance in user dense areas or areas with bad reception is the deployment of so-called femtocells. Femtocells are small base stations that are deployed indoors and share the RF spectrum with the whole mobile network. The idea is that femtocells will increase mobile operators network coverage and capacity while it at the same time increase users data throughput. There are several challenges with femtocells, both technical and economical ones. The most debated issues is how femtocells should schedule users while operating in an environment where other femtocells and base stations are interfering. In this work we developed a simulation tool to simulate the scheduling interaction between femtocells and base stationsin order to show the performance of radio resource schedulers. This rapport also aims to evaluate an approach to a femtocell scheduler to solve this issue in a satisfying way. The report gives a description of the structure of the implemented simulation tool together with some reflections on how future designs of similar or more complex simulation environments could be done.</p>

<p>In the freshwater copepod, <i>Macrocyclops albidus,</i> food availability, rearing conditions and tapeworm infection clearly affected various life-history traits and their trade-offs. I found that low food availability clearly constrained resource allocations to several life-history (often phenotypically plastic) traits, whereas high food availability either allowed for adjustments in resource allocation patterns or allowed resources to be allocated to several traits without apparent trade-offs. </p><p>Both male and female copepods allocated resources according to food availability; developing more slowly and achieving smaller adult body size when food was scarce. When food availability was low females were constrained and produced fewer eggs (in total and per clutch), and started reproduction later than females with more food available. Males under low food availability allocated relatively more to spermatophore size (current reproduction) with decreasing body size. In contrast, when food availability was high males allocated resources to body size as well as spermatophore size. Overall, at maturity, copepods of both sexes were more similar in size than in age, suggesting that large body size was more important for fitness than fast development. </p><p>In nature the prevalence of copepods infected with cestode tapeworms was found to be low (0-3%). Female copepods, experimentally infected with the cestode <i>Schistocephalus solidus</i>, showed lower overall fecundity, especially when food availability was low. However, infected females produced a larger proportion of their life-time egg production early in life than non-infected females. This might be an adaptation to reduce future fitness costs of infection. Females grown under bad rearing conditions, but with high food availability, produced their first clutch earlier than females grown under good rearing conditions, indicating an adjustment in timing of reproduction. These findings contribute to our fundamental evolutionary understanding of how environmental conditions interact with life-history traits.</p>

The purpose of the study was to explore a needs assessment method for suggesting target-based training interventions for managing conflict between the resource user/interest groups in Oregon's riparian zones. An instrument was developed and then validated by an expert panel. The questionnaire addressed three potential conflict management factors: multiple-use orientation, abundance philosophy, and conflict management styles. The instrument was distributed to members of the Oregon Water Improvement Coalition (OWIC) and to samples of its members' constituencies. Responses from the environmental, business, and professional groups were then compared to the OWIC responses as well as to each other's. Usable information was provided by 95% of the subjects (n=19) from OWIC and 55% of the subjects (n=158) from the constituencies. The OWIC and environmental group members were relatively less multiple resource use oriented than business and professional groups. The OWIC group was relatively more abundance philosophy oriented than professional and business groups. The professional and business groups in turn were significantly different than the environmentalist members. Both OWIC and professional groups were relatively more solution oriented than business and environmentalist under the riparian zones' resource use conflict situation. The instrument appeared to be sufficiently reliable and valid for its purpose. Future research should employ an interdisciplinary approach for improving the instrument by adding questions on facilitating communication between and among the interest groups. The utility of gathering information on the nonconfrontation and control conflict management styles and philosophy of land management factors deserves further study. / Graduation date: 1994

This study is concerned with the problem of resource-constrained project scheduling which includes splittable and nonsplittable jobs, renewable and nonrenewable resources, variation in resource availabi1ity, time-resource tradeoff, time-cost tradeoff, and multiple objectives. The problem is formulated as a zero-one integer programming model. A specialized solution technique is developed for the preemptive goal programming, resource-constrained project. scheduling problem for time, cost, and resource leveling objectives. In addition, single objective algorithms are also provided for the time, cost, and resource leveling objectives. These algorithms are based on the idea of the implicit enumeration process, and use the special structures of the problem to expedite the search process. Computer-generated problems are used to test each of the single objective algorithms. The results show that the algorithms give optimal solutions to tested problems with time and cost objectives using a reasonable computation time; however, heuristic solutions are more feasible for problems with resource leveling objective. The multiple objective algorithm is illustrated through application to a warehouse project problem. / Graduation date: 1993

The allocation of resources over time, referred to as resource scheduling, in large-scale construction environments is a challenging problem. Although traditional network scheduling techniques are the most popular scheduling techniques in the construction industry, they are ineffective in modeling the dynamic nature and resource interactions of large projects. Simulation based modeling or optimization techniques are also time-consuming, complicated and costly to be implemented in large-scale projects. This research is focused on developing a new framework to insert artificial intelligence inside construction simulations for facilitating the resource allocation process. The first stage in this study was developing a framework to solve resource scheduling problems in large scale construction projects. This framework, called the Simulation Based Auction Protocol (SBAP), integrates Multi-Agent Resource Allocation (MARA) in a simulation environment. This hybrid framework deploys centralized MARA (i.e., auction protocols) whereby agents bid on different combinations of resources at the start of a simulation cycle. Agents attempt to improve their individual welfare by acquiring a combination of resources. An auctioneer is designed to allocate resources to the agents by maximizing the overall welfare of the society. Simulation is also employed to track the availability of resources, and manage resource oriented activities. This framework is implemented in two large construction applications of scheduling module assembly yard and multiple heavy lift planning in modular construction. The second objective of this project is to develop a generic resource allocation component for addressing optimized resource allocation in various construction projects. This component is developed in a large scale model using High Level Architecture (HLA), instead of traditional simulation environments. HLA allows splitting a large scale model, known as a federation, into a number of manageable components (i.e., federates), while maintaining interoperability between them. A generic Resource Allocation (RA) federate is designed to act as an auctioneer for federates developed based on the SBAP. Another generic federate is also built to automate the communication with the RA federate. These two generic federates can be reused in various construction federations. This framework is successfully implemented in an industrial construction process that involves different supply chains including spool fabrication, module assembly and heavy crane lifts in site construction. / Construction Engineering and Management

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 146-157).