{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"id":[{"id":"https:\/\/ror.org\/03mb6wj31","id-type":"ROR","asserted-by":"publisher"},{"id":"https:\/\/www.isni.org\/000000041937028X","id-type":"ISNI","asserted-by":"publisher"},{"id":"https:\/\/www.wikidata.org\/entity\/Q1640731","id-type":"wikidata","asserted-by":"publisher"}],"name":"Universitat Polit\u00e8cnica de Catalunya","acronym":["UPC"]}],"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:58:52Z","timestamp":1785427132711,"version":"3.56.0"},"reference-count":0,"publisher":"Universitat Polit\u00e8cnica de Catalunya","license":[{"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/es\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>Over the last few decades, transistor miniaturization has enabled a tremendous increase in the processing capability of commercial electronic devices, which, combined with the reduction of production costs, has tremendously fostered the usage of the Information and communications Technologies (ICTs) both in terms of number of users and required data rates. In turn, this has led to a tremendous increment in the energetic demand of the ICT sector, which is expected to further grow during the upcoming years, reaching unsustainable levels of greenhouse gas emissions as reported by the European Council.\r\nAdditionally, the autonomy of battery operated devices is getting reduced year after year since battery technology has not evolved fast enough to cope with the increase of energy consumption associated to the growth of the node\u00bfs processing capability.\r\nEnergy harvesting, which is known as the process of collecting energy from the environment by different means (e.g., solar cells, piezoelectric generators, etc.), has become a potential technology to palliate both of these problems. However, when energy harvesting modules are placed in wireless communication devices (e.g., sensor nodes or hand-held devices), traditional transmission strategies are no longer applicable because the temporal variations of the node\u00bfs energy availability must be carefully accounted for in the design.\r\nApart from not considering energy harvesting, traditional transmission strategies assume that the transmission radiated power is the unique energy sink in the node. This is a reasonable assumption when the transmission range is large, but it no longer holds for low consumption devices such as sensor nodes that transmit to short distances. As a result, classical transmission strategies become suboptimal in short-range communications with low consumption devices and new strategies should be investigated.\r\nConsequently, in this dissertation we investigate and design transmission strategies for Wireless Energy Harvesting Nodes (WEHNs) by paying a special emphasis on the different sinks of energy consumption at the transmitter(s).\r\nFirst, we consider a finite battery WEHN operating in a point-to-point link through a static channel and derive the transmission strategy that minimizes the transmission completion time of a set of data packets that become available dynamically over time. The transmission strategy has to satisfy causality constrains in data transmission and energy consumption, which impose that the node cannot transmit data that is not yet available nor consume energy that has not yet been harvested.\r\nSecond, we consider a WEHN that has an infinite backlog of data to be transmitted through a point-to-point link in a time-varying linear vector Gaussian channel and study the linear precoding strategy that maximizes the mutual information given an arbitrary distribution of the input symbols while satisfying the Energy Causality Constraints (ECCs) at the transmitter.\r\nNext, apart from the transmission radiated power, we take into account additional energy sinks in the power consumption model and analyze how these energy sinks affect to the transmission strategy that maximizes the mutual information achieved by a WEHN operating in a point-to-point link.\r\nFinally, we consider multiple transmitter and receiver pairs sharing a common channel and investigate a distributed power allocation strategy that aims at maximizing the network sum-rate by taking into account the energy availability in the different transmitters and a generalized power consumption model.<\/jats:p>\n                <jats:p>Durant les \u00faltimes d\u00e8cades, la miniaturitzaci\u00f3 del transistor i la reducci\u00f3 dels seus costos de fabricaci\u00f3 han provocat un augment substancial del nombre de terminals de comunicacions i del tr\u00e0fic de dades requerit per aquests dispositius. Aix\u00ed doncs, el consum energ\u00e8tic del sector de les Tecnologies de la Informaci\u00f3 i Comunicacions ha incrementat notablement. A m\u00e9s a m\u00e9s, s\u2019espera que aquest consum segueixi creixent durant els propers anys arribant a nivells insostenibles d\u2019emissions de gasos d\u2019efecte hivernacle segons ha informat el Consell Europeu. D\u2019altra banda, la tecnologia de les bateries no ha evolucionat suficientment r\u00e0pid com per fer front a l\u2019augment del consum energ\u00e8tic associat al creixement de la capacitat de processament dels dispositius. Aix\u00f2 ha ocasionat que l\u2019autonomia dels dispositius que operen amb bateries empitjori any rere any.\r\nLes energies renovables (per exemple, energia solar, cin\u00e8tica, etc.) s\u2019han convertit en una soluci\u00f3 potencial per pal\u2022liar aquests dos problemes. No obstant aix\u00f2, quan els dispositius de comunicaci\u00f3 sense fils incorporen m\u00f2duls de captaci\u00f3 d\u2019energies renovables, les estrat\u00e8gies tradicionals de transmissi\u00f3 deixen de ser v\u00e0lides, ja que les variacions temporals de la disponibilitat d\u2019energia en el dispositiu han de ser considerades en el disseny.\r\nA m\u00e9s a m\u00e9s, les estrat\u00e8gies de transmissi\u00f3 tradicionals assumeixen que la pot\u00e8ncia radiada \u00e9s l\u2019\u00fanica font de consum energ\u00e8tic del node. Aquesta \u00e9s una suposici\u00f3 raonable per dist\u00e0ncies de transmissi\u00f3 llargues, per\u00f2 deixa de ser v\u00e0lida quan es consideren dispositius de baix consum que transmeten en dist\u00e0ncies curtes. Com a resultat, les estrat\u00e8gies de transmissi\u00f3 cl\u00e0ssiques s\u00f3n sub\u00f2ptimes en comunicacions de curt abast amb dispositius de baix consum i per aix\u00f2, s\u2019han d\u2019investigar noves estrat\u00e8gies.\r\nEn conseq\u00fc\u00e8ncia, en aquesta tesi doctoral s\u2019investiguen i es dissenyen noves estrat\u00e8gies de transmissi\u00f3 per nodes sense fils que operen amb energies renovables (WEHN) posant un \u00e8mfasi especial en les diferents fonts de consum d\u2019energia en el transmissor.\r\nEn primer lloc, la tesi investiga l\u2019estrat\u00e8gia de transmissi\u00f3 en un enlla\u00e7\u00b8 punt a punt a trav\u00e9s d\u2019un canal est\u00e0tic que minimitza el temps de transmissi\u00f3 d\u2019un conjunt de paquets de dades que s\u2019adquireixen al llarg del temps. L\u2019estrat\u00e8gia de transmissi\u00f3 ha de satisfer les limitacions per causalitat en la transmissi\u00f3 de dades i en el consum d\u2019energia les quals imposen que el node no pot transmetre dades que no han estat encara obtingudes o utilitzar energia que encara no ha estat adquirida.\r\nEn segon lloc, es considera un WEHN que sempre disposa de dades per a transmetre a trav\u00e9s d\u2019un enlla\u00e7\u00b8 punt a punt en un canal lineal Gaussi\u00e0 amb variacions temporals. En aquest escenari i, tamb\u00e9, donada una distribuci\u00f3 arbitr\u00e0ria dels s\u00edmbols d\u2019entrada, s\u2019estudia l\u2019estrat\u00e8gia de precodificaci\u00f3 lineal que maximitza la informaci\u00f3 m\u00fatua alhora que satisf\u00e0 la causalitat d\u2019energia en el transmissor.\r\nA continuaci\u00f3, a part de la pot\u00e8ncia radiada en transmissi\u00f3, s\u2019inclouen en el model de consum energ\u00e8tic els costos d\u2019activaci\u00f3 per acc\u00e9s al canal i per portadora. Donat aquest model, s\u2019analitza com aquestes fonts de consum addicionals afecten a l\u2019estrat\u00e8gia de transmissi\u00f3 que maximitza la informaci\u00f3 m\u00fatua d\u2019un WEHN que opera en un enlla\u00e7 punt a punt.\r\nFinalment, la tesi considera diversos parells transmissor i receptor que comparteixen un canal com\u00fa i investiga una estrat\u00e8gia d\u2019assignaci\u00f3 de pot\u00e8ncia distribu\u00efda la qual t\u00e9 com a objectiu maximitzar la suma de les taxes de transmissi\u00f3 dels diferents nodes tenint en compte la disponibilitat energ\u00e8tica en cada transmissor que est\u00e0 basada en un model de consum energ\u00e8tic generalitzat.<\/jats:p>","DOI":"10.5821\/dissertation-2117-95379","type":"dissertation","created":{"date-parts":[[2023,10,11]],"date-time":"2023-10-11T03:07:12Z","timestamp":1696993632000},"approved":{"date-parts":[[2014,7,24]]},"source":"Crossref","is-referenced-by-count":0,"title":["Transmission strategies for wireless energy harvesting nodes"],"prefix":"10.5821","author":[{"given":"Maria","family":"Gregori Casas","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"3865","container-title":[],"original-title":[],"contributor":[{"sequence":"additional","affiliation":[],"role":[null]}],"deposited":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T06:40:00Z","timestamp":1773902400000},"score":1,"resource":{"primary":{"URL":"https:\/\/hdl.handle.net\/2117\/95379"}},"subtitle":[],"editor":[{"given":"Miquel","family":"Payar\u00f3 Llisterri","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[null]]},"references-count":0,"URL":"https:\/\/doi.org\/10.5821\/dissertation-2117-95379","relation":{},"subject":[]}}