Every day data communication networks carry more and more information, which sometimes is very important and needs to be delivered in time. To achieve that, data transfer networks must meet quality requirements that are formed in SLA contracts between clients and service providers. Supplied data transfer link’s quality is described by worldwide defined quality metrics, which include: one way delay, IP delay variation, link loss and round trip time. In order to measure these metrics, special software was created during projects “QoS monitoring system” first phase. This paper continues the project and explores available tuning methods for created software including time synchronization and mobility problems in order to provide better accuracy with higher mobility. New system topology and time offset correction using measurement packets were proposed during the analysis part. Possible system improvements were put to test in order to evaluate the efficiency during the experiment.

With the increase in mobile broadband services the operators are gaining profits by providing high speed Internet access over the mobile network. On the other side they are also facing challenges to give QoS guarantee to the customers. In this thesis we investigate the impact of data rate and payload size on One Way Delay (OWD) and packet loss over TCP performance in 3G networks. Our goal is to evaluate the OWD and packet loss characteristics with respect to payload size and data rate from the collected network level traces. To collect these traces an experimental testbed is setup with Endace Data Acquisition and Generation (DAG) cards, for accurate measurements Endace DAG cards together with Global Positioning System (GPS) synchronization is implemented. The experiments are conducted for three different Swedish mobile operator networks and further the statistics of OWD measurements and packet loss for different data rates and payload sizes are evaluated. Our results indicate that the minimal OWD occurred at higher data rates and also shows a high delay variability. The packet loss has much impact on higher data rates and larger payload sizes, as the packet loss increases with the increase in data rate and payload size.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-07-12T13:37:34Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Master_Dissertation___Performance_Measurements_and_Analysis_of_Bluetooth_Low_Energy (8).pdf: 8669109 bytes, checksum: cb0af886f0cdc7babced229049a33535 (MD5) / Made available in DSpace on 2017-07-12T13:37:34Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Master_Dissertation___Performance_Measurements_and_Analysis_of_Bluetooth_Low_Energy (8).pdf: 8669109 bytes, checksum: cb0af886f0cdc7babced229049a33535 (MD5) Previous issue date: 2016-05-17 / The Internet of Things (IoT) paradigm has been rapidly gaining ground in the academic and industry communities as one of the most important emerging technologies. Some wireless communication technologies such as Bluetooth Low Energy (BLE) have been pointed as key technologies that will drive IoT applications. In order to leverage the BLE technology in IoT applications and identify the niche of applications this technology is more suitable, it is essential we have a deep understanding regarding some features such as link capacity, data transfer delay, connection establishment latency, and power consumption. This work evaluates the networking capabilities from BLE in scenarios of data transfer and connection establishment. The metrics maximum throughput, one-way delay, round-trip time, and connection establishment latency are evaluated through experimental measurements and we investigate how some factors (e.g. connection interval, pairing, packet size) impact on these metrics. Finally, this work proposes analytical models for the metrics investigated. / O paradigma da Internet das Coisas (Internet of Things - IoT) tem recebido grande destaque tanto das comunidades científicas como da indústria nos últimos anos. Algumas tecnologias de comunicação sem fio como Bluetooth Low Energy (BLE) tem sido apontadas como tecnologias que terão um papel fundamental na concepção de aplicativos de IoT. Um entendimento profundo de algumas características da tecnologia, como vazão e atraso na transmissão de dados, latência no estabelecimento de conexão e consumo de energia, é essencial para explorar ao máximo a tecnologia em cenários de IoT e identificar o nicho de aplicação onde esta tecnologia é mais aplicável. Este trabalho apresenta uma avaliação de desempenho da tecnologia BLE em cenários de transmissão de dados e estabelecimento de conexão. As métricas vazão máxima, atraso fim-a-fim, atraso ida-e-volta (Round-Trip Time - RTT) e latência de estabelecimento de conexão são avaliadas através de experimentos. Este trabalho também investiga como alguns fatores, como intervalo de conexão, encriptação de link e tamanho de pacote, impactam nas métricas avaliadas. Por fim, este trabalho apresenta modelos analíticos para as métricas investigadas.

Over the last few years, there has been a signifi cant rise in the mobile broadband users worldwide. Recently, operators around the world have been improving the 3G networks by providing Dual Carrier-High Speed Packet Access+ (DC-HSPA+) services in both uplink and downlink to the users. However, the delay performance of the operational DC-HSPA+ networks is not focused. Firstly, we investigate and analyze the e ffect of operator service on One-Way Delay (OWD) and Jitter. Secondly, we investigate the treatment of protocols by 3G network for random packet sizes and random Inter Packet Duration (IPD). Thirdly, we investigate the eff ect of background load on OWD for packets generated at very low rate. Fourthly, we investigate the impact of constant IPD and streaming. Fifthly, we investigate the effects of shrinking the interval of IPD on OWD in 3G networks. Lastly, we investigate the OWD for Constant-Bit-Rate (CBR) and Variable-Bit-Rate (VBR) transmission patterns. Firstly, results show that OWD in the DC-HSPA+ networks is lower compared to the OWD in the preceding HSUPA networks and OWD strongly depends on packet-size at lower rates. Secondly, the 3G networks treat User Datagram Protocol (UDP), Transmission Control Protocol (TCP) and Internet Control Message Protocol (ICMP) protocols similarly for random packet size and random IPD. Thirdly, at high rates OWD depends on E-TFCE-DCH Transport Format Combination (ETFC) grants. Thirdly, the results also indicate that background load has a signi ficant impact on the end-to-end OWD. Fourthly, for low rates, OWD depends on packet sizes and for high rates OWD depends on IPD and for higher rates, OWD depends on E-TFC grants. Fifthly, we also observe: Shrinking the interval of IPD does not necessarily improve the OWD performance. Lastly, results also indicate that the VBR pattern has a better OWD performance than the CBR pattern for low transmission rates.