Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-07T11:55:49Z No. of bitstreams: 1 robertomussideoliveira.pdf: 1293292 bytes, checksum: 78c6c9fd9415c0b3990a1aaf55b842a2 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-07T13:31:58Z (GMT) No. of bitstreams: 1 robertomussideoliveira.pdf: 1293292 bytes, checksum: 78c6c9fd9415c0b3990a1aaf55b842a2 (MD5) / Made available in DSpace on 2017-06-07T13:31:58Z (GMT). No. of bitstreams: 1 robertomussideoliveira.pdf: 1293292 bytes, checksum: 78c6c9fd9415c0b3990a1aaf55b842a2 (MD5) Previous issue date: 2015-03-11 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesse trabalho, discutimos o uso de protocolos de cooperação na subcamada de controle de acesso ao meio (CMAC) para reduzir a taxa de perda de pacote e aumentar o goodput em um sistema de comunicação banda larga via rede elétrica (PLC) de ambientes residenciais. Para apoiar essa discussão, nós, pela primeira vez, apresentamos uma análise estatística da taxa de erro de pacote (PER) de canais PLC residenciais a partir de dados medidos em um modelo com um único relay. Adicionalmente, nós esboçamos um simples protocolo CMAC capaz de explorar a diversidade oferecida por uma rede elétrica doméstica. Usando esse protocolo, nosso objetivo é mostrar o impacto da variação da largura de banda, da variação da PER e da posição relativa do relay no desempenho do sistema. Sendo assim, nós mostramos que a taxa de perda de pacote e o goodput melhoram quando a largura de banda de frequência aumenta. Além disso, resultados mostram que a cooperação na camada de enlace não oferece vantagens caso os valores de PER do enlace direto e do enlace intermediado pelo relay sejam muito altos ou muito baixos. Nós também notamos que as melhorias estudadas dependem da posição do nó relay em relação ao nó fonte e ao nó destino (i.e., notamos melhoras na rede nos casos em que o relay estava situado próximo à fonte e no meio do caminho entre a fonte e o destino). Finalmente, uma comparação entre os esquemas de acesso múltiplo por divisão de frequências ortogonais - acesso múltiplo por divisão de tempo (OFDMA-TDMA) e acesso múltiplo por divisão de tempo - multiplexação por divisão ortogonal de frequência (TDMA-OFDM) mostra que o simples protocolo CMAC é mais eficaz quando usado juntamente com o primeiro esquema do que com o último. Em suma, a nossa contribuição é dividida em duas etapas: primeiramente, desenvolvemos um simples protocolo MAC de cooperação que traz melhorias de desempenho na rede quando comparado com um sistema sem a cooperação; em segundo lugar, nós realizamos uma análise sistemática de diferentes cenários, mostrando os benefícios e limitações da cooperação na camada de enlace de redes PLC. / In this work, we discuss the use of cooperative medium access control (CMAC) protocols to reduce packet loss rate and to improve goodput of in-home broadband power line communication (PLC) systems. To support this discussion, we, for the first time, present a statistical packet error rate (PER) analysis of measured in-home PLC channels by adopting a single relay model. Additionally, we outline a simple CMAC protocol that is capable of exploiting the diversity offered by in-home electric power grids. Using this protocol, we aim to show the impact of bandwidth variation, PER variation and of relative relay location on system performance. Thus, we show that packet loss rate and goodput improve when frequency bandwidth increases. Also, results show that cooperation at the link layer does not offer advantages if the PER values of direct and relayed links are very high or very low. Furthermore, we note that the improvements depend on the location of the node relay in relation to the nodes source and the destination (i.e., network improves if the relay is located near the source or in the midway between the source and the destination). Finally, a comparison between orthogonal frequency division multiple access - time division multiple access (OFDMA-TDMA) and time division multiple access - orthogonal frequency division multiplexing (TDMA-OFDM) schemes show that the simple CMAC protocol is more effective when it is used together with the former scheme than the latter.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-01T12:45:13Z No. of bitstreams: 1 robertomussideoliveira.pdf: 1293292 bytes, checksum: 78c6c9fd9415c0b3990a1aaf55b842a2 (MD5) / Made available in DSpace on 2015-12-01T12:45:13Z (GMT). No. of bitstreams: 1 robertomussideoliveira.pdf: 1293292 bytes, checksum: 78c6c9fd9415c0b3990a1aaf55b842a2 (MD5) Previous issue date: 2015-03-11 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesse trabalho, discutimos o uso de protocolos de coopera¸c˜ao na subcamada de controle de acesso ao meio (CMAC) para reduzir a taxa de perda de pacote e aumentar o goodput em um sistema de comunica¸c˜ao banda larga via rede el´etrica (PLC) de ambientes residenciais. Para apoiar essa discuss˜ao, n´os, pela primeira vez, apresentamos uma an´alise estat´ıstica da taxa de erro de pacote (PER) de canais PLC residenciais a partir de dados medidos em um modelo com um ´unico relay. Adicionalmente, n´os esbo¸camos um simples protocolo CMAC capaz de explorar a diversidade oferecida por uma rede el´etrica dom´estica. Usando esse protocolo, nosso objetivo ´e mostrar o impacto da varia¸c˜ao da largura de banda, da varia¸c˜ao da PER e da posi¸c˜ao relativa do relay no desempenho do sistema. Sendo assim, n´os mostramos que a taxa de perda de pacote e o goodput melhoram quando a largura de banda de frequˆencia aumenta. Al´em disso, resultados mostram que a coopera¸c˜ao na camada de enlace n˜ao oferece vantagens caso os valores de PER do enlace direto e do enlace intermediado pelo relay sejam muito altos ou muito baixos. N´os tamb´em notamos que as melhorias estudadas dependem da posi¸c˜ao do n´o relay em rela¸c˜ao ao n´o fonte e ao n´o destino (i.e., notamos melhoras na rede nos casos em que o relay estava situado pr´oximo `a fonte e no meio do caminho entre a fonte e o destino). Finalmente, uma compara¸c˜ao entre os esquemas de acesso m´ultiplo por divis˜ao de frequˆencias ortogonais - acesso m´ultiplo por divis˜ao de tempo (OFDMA-TDMA) e acesso m´ultiplo por divis˜ao de tempo - multiplexa¸c˜ao por divis˜ao ortogonal de frequˆencia (TDMA-OFDM) mostra que o simples protocolo CMAC ´e mais eficaz quando usado juntamente com o primeiro esquema do que com o ´ultimo. Em suma, a nossa contribui¸c˜ao ´e dividida em duas etapas: primeiramente, desenvolvemos um simples protocolo MAC de coopera¸c˜ao que traz melhorias de desempenho na rede quando comparado com um sistema sem a coopera¸c˜ao; em segundo lugar, n´os realizamos uma an´alise sistem´atica de diferentes cen´arios, mostrando os benef´ıcios e limita¸c˜oes da coopera¸c˜ao na camada de enlace de redes PLC. / In this work, we discuss the use of cooperative medium access control (CMAC) protocols to reduce packet loss rate and to improve goodput of in-home broadband power line communication (PLC) systems. To support this discussion, we, for the first time, present a statistical packet error rate (PER) analysis of measured in-home PLC channels by adopting a single relay model. Additionally, we outline a simple CMAC protocol that is capable of exploiting the diversity offered by in-home electric power grids. Using this protocol, we aim to show the impact of bandwidth variation, PER variation and of relative relay location on system performance. Thus, we show that packet loss rate and goodput improve when frequency bandwidth increases. Also, results show that cooperation at the link layer does not offer advantages if the PER values of direct and relayed links are very high or very low. Furthermore, we note that the improvements depend on the location of the node relay in relation to the nodes source and the destination (i.e., network improves if the relay is located near the source or in the midway between the source and the destination). Finally, a comparison between orthogonal frequency division multiple access - time division multiple access (OFDMA-TDMA) and time division multiple access - orthogonal frequency division multiplexing (TDMA-OFDM) schemes show that the simple CMAC protocol is more effective when it is used together with the former scheme than the latter.

This thesis is dedicated to measuring the communication performance of LoRa technology in an indoor environment and providing insight into its potential application as an effective Internet of Things (IoT) communication solution in Low Power Wide Area Networks (LPWAN). Through careful experimentation and analysis, we assessed various transmission parameters such as spreading factor (SF), bandwidth (BW), Payload Length (PL), and LoRaWAN classes. Performance metrics including Receive Signal Strength Indicator (RSSI), Signal-to-Noise Ratio (SNR), Round-trip time (RTT), and Goodput are measured to evaluate LoRa’s performance under different settings. The research question addressed is whether LoRa can be effectively used for indoor wireless communication. Our findings demonstrate that LoRa technology exhibits good transmission range, reliability, and cost-effectiveness in indoor environments, making it suitable for some indoor IoT applications. We also examined the impact of different LoRaWAN device classes and highlighted the importance of balancing the SF and BW to optimize communication performance. In conclusion, this thesis offers a comprehensive understanding of the communication performance of LoRa technology in indoor environments, providing valuable guidance for its practical application in indoor IoT communication. The research findings presented herein serve as a significant reference for future research endeavors in this field, enabling further advancements in the domain of LoRa-based wireless communication technologies for indoor IoT applications. / Denna avhandling ägnas åt att mäta kommunikationsprestanda för LoRa-teknik i en inomhusmiljö och ger insikt i dess potentiella tillämpning som en effektiv kommunikationslösning för Internet of Things (IoT) i Low Power Wide Area Networks (LPWAN). Genom noggranna experiment och analys utvärderade vi olika överföringsparametrar som spridningsfaktor (SF), bandbredd (BW), nyttolastlängd och LoRaWAN-enhetens klasser. Prestandametriker inklusive Receive Signal Strength Indicator (RSSI), Signal-to-Noise Ratio (SNR), Round-trip time (RTT) och Goodput mäts för att utvärdera LoRa’s prestanda under olika inställningar. Forskningsfrågan som behandlas är om LoRa effektivt kan användas för inomhus trådlös kommunikation. Våra resultat visar att LoRa-teknik uppvisar bra överföringsområde, tillförlitlighet och kostnadseffektivitet i inomhusmiljöer, vilket gör det lämpligt för vissa inomhus-IoT-applikationer. Vi undersökte också inverkan av olika LoRaWAN-enhet klasser och framhävde vikten av att balansera SF och BW för att optimera kommunikationsprestanda. Sammanfattningsvis erbjuder denna avhandling en omfattande förståelse för kommunikationsprestanda för LoRa-teknik i inomhusmiljöer, vilket ger värdefull vägledning för dess praktiska tillämpning inom inomhus IoT-kommunikation. De forskningsresultat som presenteras här fungerar som en betydande referens för framtida forskningsinsatser inom detta område, vilket möjliggör ytterligare framsteg inom området för LoRa-baserade trådlösa kommunikationstekniker för inomhus IoT-applikationer.

Previous research on ECN and RED usually considered only a limited traffic domain, focusing on networks with a small number of homogeneous flows. The behavior of RED and ECN congestion control mechanisms in TCP network with many competing heterogeneous flows in the bottleneck link, hasn't been sufficiently explored. This thesis first investigates the behavior and performance of RED with ECN congestion control mechanisms with many heterogeneous TCP Reno flows using the network simulation tool, ns-2. By comparing the simulated performance of RED and ECN routers, this study finds that ECN does provide better goodput and fairness than RED for heterogeneous flows. However, when the demand is held constant, the number of flows generating the demand has a negative effect on performance. Meanwhile, the simulations with many flows demonstrate that the bottleneck router's marking probability must be aggressively increased to provide good ECN performance. Based on these simulation results, an Adaptive ECN algorithm (AECN) was studied to further improve the goodput and fairness of ECN. AECN divides all flows competing for a bottleneck into three flow groups, and deploys a different max for each flow group. Meanwhile, AECN also adjusts min for the robust flow group and max to get higher performance when the number of flows grows large. Furthermore, AECN uses mark-front strategy, instead of mark-tail strategy in standard ECN. A series of AECN simulations were run in ns-2. The simulations show clearly that AECN treats each flow fairer than ECN with the two fairness measurements: Jain's fairness index and visual max-min fairness. AECN has fewer packet drops and alleviates the lockout phenomenon and yields higher goodput than ECN.

In this thesis we investigated whether using compression when sending inter-process communication (IPC) messages can be beneficial or not. A literature study on lossless compression resulted in a compilation of algorithms and techniques. Using this compilation, the algorithms LZO, LZFX, LZW, LZMA, bzip2 and LZ4 were selected to be integrated into LINX as an extra layer to support lossless message compression. The testing involved sending messages with real telecom data between two nodes on a dedicated network, with different network configurations and message sizes. To calculate the effective throughput for each algorithm, the round-trip time was measured. We concluded that the fastest algorithms, i.e. LZ4, LZO and LZFX, were most efficient in our tests. / I detta examensarbete har vi undersökt huruvida komprimering av meddelanden för interprocesskommunikation (IPC) kan vara fördelaktigt. En litteraturstudie om förlustfri komprimering resulterade i en sammanställning av algoritmer och tekniker. Från den här sammanställningen utsågs algoritmerna LZO, LZFX, LZW, LZMA, bzip2 och LZ4 för integrering i LINX som ett extra lager för att stödja komprimering av meddelanden. Algoritmerna testades genom att skicka meddelanden innehållande riktig telekom-data mellan två noder på ett dedikerat nätverk. Detta gjordes med olika nätverksinställningar samt storlekar på meddelandena. Den effektiva nätverksgenomströmningen räknades ut för varje algoritm genom att mäta omloppstiden. Resultatet visade att de snabbaste algoritmerna, alltså LZ4, LZO och LZFX, var effektivast i våra tester.

Cette thèse porte sur l'allocation de ressources dans les réseaux mobiles ad hoc basés sur les protocoles ARQ Hybrides (HARQ), qui offrent une souplesse de déploiement rapide pour des communications à court terme dans le cadre d'applications militaires ou de futurs réseaux intelligents. L'OFDMA (Orthogonal Frequency Division Multiple Access) est considérée en particulier, en tant que solution prometteuse dans les standards de communication sans fil les plus récents. Bien qu'une coordination centralisée des communications soit rendue possible grâce à une organisation en clusters, il est toutefois difficile de remonter au coordinateur des informations fiables sur l'état du canal en vertu de la latence due à l'organisation de ce réseau. Ainsi les performances des liens seront renforcées par des mécanismes de retransmission HARQ, qui permettent de gérer les variations rapides du canal. L'objectif principal de cette thèse est l'allocation des ressources OFDMA dans les réseaux mobiles ad hoc basés sur les protocoles HARQ, en utilisant uniquement les statistiques à long terme du canal. Pour répondre à un besoin industriel, des schémas de modulation et de codage pratiques seront considérés en lieu et place des outils de capacité hérités de la théorie de l'information. En particulier, nous concevons et analysons de nouveaux algorithmes qui optimisent l'attribution de puissance, de largeur de bande, d'ordre de modulation et de rendement de codage, pour les mécanismes HARQ insérés dans le schéma multi-utilisateurs proposé. En raison de la présence de protocoles HARQ dans le réseau, une partie de la thèse est dédiée à l'étude des performances de l'HARQ que nous étendons à de nouveaux contextes.

Inom nätverksbranchen finns en strävan att gå från proprietära lösningar till en öppen standard för hård- och mjukvara. En term för detta är Whiteboxing och det innebär att användaren ges möjlighet att plocka ihop komponenter efter behov, och själv välja vilken mjukvara som används. I sin enklaste form byggs en Whiteboxrouter av en konventionell PC med två nätverkskort och en mjukvarubaserad routingapplikation. Företaget ÅF är intresserade av att veta hur Whitebox-lösningar för routrar står sig prestandamässigt i relation till konventionella routerlösningar med Application Specific Integrated Circuit. Detta arbete har undersökt prestandan genom att mäta throughput och goodput hos en Cisco 2911-router, en Whiteboxrouter med mjukvaran pfSense, samt en Whiteboxrouter som körde pfSense virtualiserat på ESXi. Dessutom undersöktes respektive konfigurations prestanda när trafiken skickades över IPsec VPN. För mätningarna användes filöverföringar med FTP och mätprogrammet Iperf3. Målet med arbetet var att skapa ett beslutsunderlag som klargjorde eventuella prestandaskillnader och utarbetade rekommendationer för framtida val av routerlösning. Resultatet visade att vid generell paketförmedling var prestandan mellan routrarna relativt jämn, dock rekommenderas den virtualiserade Whiteboxroutern då den fick det bästa resultatet. När trafiken sedan krypterades med IPsec VPN var det stora prestandaskillnader mellan enheterna. Bäst prestanda fick Whiteboxroutern. Författaren ser en vinning med Whitebox-tekniken i stort då den medger att serverutrustning som ska utrangeras på grund av prestandakrav, istället kan fungera som nätverksutrustning (routrar och brandväggar) och fortsätta användas under en större del av den tekniska livslängden. Detta kan på sikt leda till minskad miljöpåverkan och besparingar för företaget.

Dans le canal sans fil, la communication coopérative permet à un ou plusieurs relais d’aider la transmission entre la source et la destination. L'objectif de cette thèse est de développer des outils d'analyse de performance pour les systèmes coopératifs utilisant des techniques HARQ. Le premier chapitre de cette thèse donne des informations sur le codage de réseau dans les réseaux coopératifs, et introduit la motivation pour ce travail. L’objectif du deuxième chapitre est d’analyser et d’évaluer les performances de la qualité de service (QoS) des schémas ARQ-STBC, HARQ et FEC, dans le contexte de l’efficacité énergétique, aux niveaux des couches MAC et IP. Afin d’atteindre ce but, une nouvelle méthode d'analyse est dérivé et appliqué au scénario de communication point à point (P2P). Ceci nous permet de comparer les schémas avec et sans retransmissions, et d’établir la consommation d’énergie de chaque système considéré. Cela nous permet de déterminer dans quelles conditions il est énergétiquement plus efficace d’utiliser la protection cross-layer, ou le simple codage de canal. Dans le troisième chapitre une classe de protocoles coopératifs déterministes est introduite. Les protocoles que nous considérons sont différents en termes du comportement de relais(s) de source(s), et de la destination. Nous considérons deux types de protocoles coopératifs: decode-and-forward (DCF), et demodulate-and-forward (DMF). Les performances de chacun de ces protocoles sont analysés, avec et sans combining à la destination. Les évaluations de QoS qui sont examinés sont: le taux d'erreur de trame, le délai, l'efficacité, et le goodput. Les dérivations analytiques sont effectuées à l'aide de la machine à états finis de Markov, ainsi que grâce à l’approche combinatoire. Cependant, il est démontré, que la complexité de ces dérivations augmente au moment ou le crédit de retransmissions et/ou des nœuds dans le réseau est augmentée. Donc cette approche devient non-traitable pour des grands schémas coopératifs. Le quatrième chapitre présente une classe de protocoles de communication probabilistes, où les nœuds retransmettent avec une certaine probabilité. Il est démontré l'existence d'une classe de protocoles probabilistes équivalents, qui permettent d’obtenir les mêmes performances des protocoles déterministes précédemment traités. En utilisant la preuve de concept, nous démontrons que le protocole probabiliste permet d’effectuer les évaluations analytiques de réseaux multi-nœuds, même dans le cas d'un grand nombre de nœuds dans le réseau. Basée sur cela, nous déduisons les paramètres QoS, et les évaluons également par des simulations Monte-Carlo. Les paramètres d'évaluation de performances dérivées sont optimisés en limitant le taux d'erreur de trame, et en essayant de trouver le nombre de transmissions optimal et le code rate qui maximisent le goodput. Il est également démontré que la classe de protocoles probabilistes peut atteindre une région d’optimalité plus grand que la classe de protocoles déterministes. / In the wireless channel, cooperative communications allow one or many relays to assist the communication between the source and the destination. The aim of this thesis is the development of tools for the analysis of cooperative systems, when HARQ techniques are employed to provide cross-layer error protection. The first chapter of the thesis gives background information on network coding in cooperative relay networks, and introduces the motivation for this work. The second chapter is devoted to the analysis of the energetic-fair performance evaluations of FEC, ARQ-STBC and HARQ schemes at the MAC and IP layers. New analytical framework is derived and applied to a point-to-point network scenario. This framework allows to make energetic fair comparisons between the schemes with and without retransmissions. We determine under which channel conditions the cross-layer error protection is energetically more efficient than the simple channel coding. In the third chapter of this thesis we study the cooperative deterministic protocols. The protocols that we consider differ based on the behaviour of the relay(s), source(s), and destination. We consider two major types of cooperative protocols: decode-and forward (DCF), and demodulate-and-forward (DMF). Each of these protocols in its turn is analysed with and without combining mechanisms at the destination. We derive the soft decoders at the destination side for each respective case, and compare the performances of these protocols at the MAC layer. The following quality of service metrics are evaluated: frame error rate, delay, efficiency, goodput. The analysis is done evaluating the steady-state, using finite state Markov chains and a combinatorial approach. The analysis, however, becomes very complex as the number of transmissions and/or nodes in the network increases. The fourth chapter introduces a class of probabilistic communication protocols, where the devices retransmit with a given probability. We prove the existence of an equivalent class of protocols, with the same performances as the deterministic class. Using proofs of concept it is shown that the probabilistic protocol class allows for tractable steady-state analysis, even for many nodes in the network. Based on this, we then derive the QoS metrics and evalute them also by simulations. The derived performance evaluation metrics are then optimized by constraining the frame error rate, and trying to find the most optimal transmissions number and code rates which maximize the goodput. It is furthermore shown, that the equivalent protocol has larger optimal region than the deterministic one.

In the wireless channel, cooperative communications allow one or many relays to assist the communication between the source and the destination. The aim of this thesis is the development of tools for the analysis of cooperative systems, when HARQ techniques are employed to provide cross-layer error protection. The first chapter of the thesis gives background information on network coding in cooperative relay networks, and introduces the motivation for this work. The second chapter is devoted to the analysis of the energetic-fair performance evaluations of FEC, ARQ-STBC and HARQ schemes at the MAC and IP layers. New analytical framework is derived and applied to a point-to-point network scenario. This framework allows to make energetic fair comparisons between the schemes with and without retransmissions. We determine under which channel conditions the cross-layer error protection is energetically more efficient than the simple channel coding. In the third chapter of this thesis we study the cooperative deterministic protocols. The protocols that we consider differ based on the behaviour of the relay(s), source(s), and destination. We consider two major types of cooperative protocols: decode-and forward (DCF), and demodulate-and-forward (DMF). Each of these protocols in its turn is analysed with and without combining mechanisms at the destination. We derive the soft decoders at the destination side for each respective case, and compare the performances of these protocols at the MAC layer. The following quality of service metrics are evaluated: frame error rate, delay, efficiency, goodput. The analysis is done evaluating the steady-state, using finite state Markov chains and a combinatorial approach. The analysis, however, becomes very complex as the number of transmissions and/or nodes in the network increases. The fourth chapter introduces a class of probabilistic communication protocols, where the devices retransmit with a given probability. We prove the existence of an equivalent class of protocols, with the same performances as the deterministic class. Using proofs of concept it is shown that the probabilistic protocol class allows for tractable steady-state analysis, even for many nodes in the network. Based on this, we then derive the QoS metrics and evalute them also by simulations. The derived performance evaluation metrics are then optimized by constraining the frame error rate, and trying to find the most optimal transmissions number and code rates which maximize the goodput. It is furthermore shown, that the equivalent protocol has larger optimal region than the deterministic one.