45 research outputs found
Dynamic Adaptive Video Streaming on Heterogeneous TVWS and Wi-Fi Networks
Nowadays, people usually connect to the Internet through a multitude of different devices. Video streaming takes the lion's share of the bandwidth, and represents the real challenge for the service providers and for the research community. At the same time, most of the connections come from indoor, where Wi-Fi already experiences congestion and coverage holes, directly translating into a poor experience for the user. A possible relief comes from the TV white space (TVWS) networks, which can enhance the communication range thanks to sub-GHz frequencies and favorable propagation characteristics, but offer slower datarates compared with other 802.11 protocols. In this paper, we show the benefits that TVWS networks can bring to the end user, and we present CABA, a connection aware balancing algorithm able to exploit multiple radio connections in the favor of a better user experience. Our experimental results indicate that the TVWS network can effectively provide a wider communication range, but a load balancing middleware between the available connections on the device must be used to achieve better performance. We conclude this paper by presenting real data coming from field trials in which we streamed an MPEG dynamic adaptive streaming over HTTP video over TVWS and Wi-Fi. Practical quantitative results on the achievable quality of experience for the end user are then reported. Our results show that balancing the load between Wi-Fi and TVWS can provide a higher playback quality (up to 15% of average quality index) in scenarios in which the Wi-Fi is received at a low strength
Survey of Spectrum Sharing for Inter-Technology Coexistence
Increasing capacity demands in emerging wireless technologies are expected to
be met by network densification and spectrum bands open to multiple
technologies. These will, in turn, increase the level of interference and also
result in more complex inter-technology interactions, which will need to be
managed through spectrum sharing mechanisms. Consequently, novel spectrum
sharing mechanisms should be designed to allow spectrum access for multiple
technologies, while efficiently utilizing the spectrum resources overall.
Importantly, it is not trivial to design such efficient mechanisms, not only
due to technical aspects, but also due to regulatory and business model
constraints. In this survey we address spectrum sharing mechanisms for wireless
inter-technology coexistence by means of a technology circle that incorporates
in a unified, system-level view the technical and non-technical aspects. We
thus systematically explore the spectrum sharing design space consisting of
parameters at different layers. Using this framework, we present a literature
review on inter-technology coexistence with a focus on wireless technologies
with equal spectrum access rights, i.e. (i) primary/primary, (ii)
secondary/secondary, and (iii) technologies operating in a spectrum commons.
Moreover, we reflect on our literature review to identify possible spectrum
sharing design solutions and performance evaluation approaches useful for
future coexistence cases. Finally, we discuss spectrum sharing design
challenges and suggest future research directions
A policy-based framework towards smooth adaptive playback for dynamic video streaming over HTTP
The growth of video streaming in the Internet in the last few years has been highly
significant and promises to continue in the future. This fact is related to the growth of
Internet users and especially with the diversification of the end-user devices that happens
nowadays.
Earlier video streaming solutions didn´t consider adequately the Quality of
Experience from the user’s perspective. This weakness has been since overcame with the
DASH video streaming. The main feature of this protocol is to provide different versions,
in terms of quality, of the same content. This way, depending on the status of the network
infrastructure between the video server and the user device, the DASH protocol
automatically selects the more adequate content version. Thus, it provides to the user the
best possible quality for the consumption of that content.
The main issue with the DASH protocol is associated to the loop, between each
client and video server, which controls the rate of the video stream. In fact, as the network
congestion increases, the client requests to the server a video stream with a lower rate.
Nevertheless, due to the network latency, the DASH protocol in a standalone way may
not be able to stabilize the video stream rate at a level that can guarantee a satisfactory
QoE to the end-users.
Network programming is a very active and popular topic in the field of network
infrastructures management. In this area, the Software Defined Networking paradigm is
an approach where a network controller, with a relatively abstracted view of the physical
network infrastructure, tries to perform a more efficient management of the data path.
The current work studies the combination of the DASH protocol and the Software
Defined Networking paradigm in order to achieve a more adequate sharing of the network
resources that could benefit both the users’ QoE and network management.O streaming de vÃdeo na Internet é um fenómeno que tem vindo a crescer de forma
significativa nos últimos anos e que promete continuar a crescer no futuro. Este facto está
associado ao aumento do número de utilizadores na Internet e, sobretudo, à crescente
diversificação de dispositivos que se verifica atualmente. As primeiras soluções utilizadas no streaming de vÃdeo não acomodavam adequadamente o ponto de vista do utilizador na avaliação da qualidade do vÃdeo, i.e., a Qualidade de Experiência (QoE) do utilizador. Esta debilidade foi suplantada com o protocolo de streaming de vÃdeo adaptativo DASH. A principal funcionalidade deste protocolo é fornecer diferente versões, em termos de qualidade, para o mesmo conteúdo. Desta forma, dependendo do estado da infraestrutura de rede entre o servidor de vÃdeo e o dispositivo do utilizador, o protocolo DASH seleciona automaticamente a versão do conteúdo mais adequada a essas condições. Tal permite fornecer ao utilizador a melhor
qualidade possÃvel para o consumo deste conteúdo. O principal problema com o protocolo DASH está associado com o ciclo, entre cada cliente e o servidor de vÃdeo, que controla o débito de cada fluxo de vÃdeo. De facto, à medida que a rede fica congestionada, o cliente irá começar a requerer ao servidor um
fluxo de vÃdeo com um débito menor. Ainda assim, devido à latência da rede, o protocolo
DASH pode não ser capaz por si só de estabilizar o débito do fluxo de vÃdeo num nÃvel
que consiga garantir uma QoE satisfatória para os utilizadores. A programação de redes é uma área muito popular e ativa na gestão de infraestruturas de redes. Nesta área, o paradigma de Software Defined Networking é uma abordagem onde um controlador da rede, com um ponto de vista relativamente abstrato
da infraestrutura fÃsica da rede, tenta desempenhar uma gestão mais eficiente do encaminhamento de rede.
Neste trabalho estuda-se a junção do protocolo DASH e do paradigma de Software Defined Networking, de forma a atingir uma partilha mais adequada dos recursos da rede. O objetivo é implementar uma solução que seja benéfica tanto para a qualidade de experiência dos utilizadores como para a gestão da rede
Performance evaluation of synergic operation of algorithms enabling opportunistic networks - D4.3
Deliverable D4.3 del projecte OneFITPreprin
Cognitive radio for disaster response networks: survey, potential, and challenges
In the wake of a natural or man-made disaster, restoration of telecommunications is essential. First responders must coordinate their responses, immediate casualties require assistance, and all affected citizens may need to access information and contact friends and relatives. Existing access and core infrastructure may be damaged or destroyed, so to support the required services, new infrastructure must be rapidly deployed and integrated with undamaged resources still in place. This new equipment should be flexible enough to interoperate with legacy systems and heterogeneous technologies. The ability to selforganize is essential in order to minimize any delays associated with manual configuration. Finally, it must be robust and reliable enough to support mission-critical applications. Wireless systems can be more easily reconfigured than wired solutions to adapt to the various changes in the operating environment that can occur in a disaster scenario. A cognitive radio is one that can observe its operating environment, make decisions and reconfigure in response to these observations, and learn from experience. This article examines the use of cognitive radio technologies for disaster response networks and shows that they are ideally suited to fulfill the unique requirements of these networks. Key enabling technologies for realizing real-world cognitive radio networks for disaster response are discussed and core challenges are examined